Process for producing aromatic carbonate

ABSTRACT

Production of an aromatic carbonic ester through an ester exchange reaction between a starting material and a reactant while distilling by-product alcohols and/or by-product dialkyl carbonates off the reaction system, wherein use is made of a specified catalyst.

TECHNICAL FIELD

The present invention relates to a method for producing an aromaticcarbonate. More specifically, the present invention relates to a methodcapable of producing a high purity aromatic carbonate in a stable mannerfor a long period, which comprises allowing to react a starting materialselected from the group consisting of a dialkyl carbonate, an alkylarylcarbonate and a mixture thereof and a reactant selected from the groupconsisting of an aromatic monohydroxy compound, an alkylaryl carbonateand a mixture thereof in the presence of a metal-containing catalystwhich has a molecular weight of 450 or more and which is in the form ofliquid or dissolved in a liquid phase in the reaction system, withdistilling off by-product alcohol and/or by-product dialkyl carbonate tothe outside of the reaction system.

BACKGROUND ART

Aromatic carbonate is useful as a raw material for producing aromaticpolycarbonate which is recently becoming more and more important as anengineering plastic, without using poisonous phosgene, or as a rawmaterial for producing isocyanate without using poisonous phosgene.Referring to the method of producing an aromatic carbonate, a method isknown, which comprises subjecting dialkyl carbonate, alkylaryl carbonateor a mixture thereof which is a starting material and an aromaticmonohydroxy compound, an alkylaryl carbonate or a mixture thereof whichis a reactant to an transesterification to produce a correspondingaromatic carbonate or an aromatic carbonate mixture.

However, all such transesterification are an equilibrium reaction, anddue to the reactant-favored equilibrium and its low reaction rate,industrial production of aromatic carbonate by this method has been verydifficult. Several approaches have been proposed in order to make thismethod improvements, and most of them relate to catalysts for increasingthe reaction rate and a number of metal-containing catalysts are known.In a method for producing alkylaryl carbonate, diaryl carbonate or amixture thereof by a reaction between dialkyl carbonate and an aromatichydroxy compound, the following catalysts are proposed as suchcatalysts: Lewis acid such as transition metal halide or a compoundwhich produces Lewis acid (Patent Document 1, Patent Document 2, PatentDocument 3 (which is corresponding to Patent Documents 4 to 6)), tincompounds such as organic tin alkoxide and organic tin oxide (PatentDocument 7 (which is corresponding to Patent Document 8)), PatentDocument 9, Patent Document 10 (which is corresponding to PatentDocument 11), Patent Document 12 (which is corresponding to PatentDocument 13), Patent Document 14, and Patent Document 15), salts andalkoxides of alkali metal or alkaline earth metal (Patent Document 16),lead compounds (Patent Document 16), complexes of metal such as copper,iron or zirconium (Patent Document 17), titanates (Patent Document 18which is corresponding to Patent Document 19), a mixture of Lewis acidand protonic acid (Patent Document 20 which is corresponding to PatentDocument 21), a compound of Sc, Mo, Mn, Bi, Te (Patent Document 22) andferric acetate (Patent Document 23).

In addition, in a method of producing diaryl carbonate bydisproportionation of diaryl carbonate and diaryl carbonate by antransesterification between the same kind of molecules of alkylarylcarbonate, the following catalysts are proposed as such catalysts: Lewisacid and a transition metal compound which can produce Lewis acid(Patent Document 24 which is corresponding to Patent Documents 25 and26), a polymeric tin compound (Patent Document 27 which is correspondingto Patent Document 28), a compound represented by the formula R—X(═O)OH(in which X is selected form Sn and Ti and R is selected from monovalenthydrocarbon groups) (Patent Document 29 which is corresponding to PatentDocument 30), a mixture of Lewis acid and protonic acid (Patent Document31 which is corresponding to Patent Document 32), a lead catalyst(Patent Document 33), a titanium or zirconium compound (Patent Document34), a tin compound (Patent Document 35) and a compound of Sc, Mo, Mn,Bi, Te (Patent Document 36).

On the other hand, it is also attempted to improve the yield of aromaticcarbonate by shifting the equilibrium to the product side as much aspossible by designing a suitable reaction system. For example, a methodin which by-product methanol is distilled off together with anazeotropic agent by azeotropic distillation in a reaction betweendimethyl carbonate and phenol (Patent Document 37 and correspondingPatent Documents 38 and 39, Patent Document 40) and a method in whichby-product methanol is removed by adsorption using molecular sieve(Patent Document 41 which is corresponding to Patent Document 42) areproposed.

Further, a method in which alcohol produced by the above-mentionedreaction is distilled off from a reaction mixture using an apparatushaving a distillation column on the upper part of a reactor is alsoknown (Examples of Patent Document 43 which is corresponding to PatentDocument 44, Examples of Patent Document 45, Examples of Patent Document46 and corresponding Patent Document 47, Examples of Patent Document 48which is corresponding Patent Document 49, Examples of Patent Document50 which is corresponding Patent Document 51), Examples of PatentDocuments 52, 53 and 54).

More preferable methods include a method in which dialkyl carbonate andan aromatic hydroxy compound are continuously supplied to a multi-stagedistillation column and continuously reacted in the column whilecontinuously removing produced low boiling point components includingalcohol by distillation and extracting generated products containingalkylaryl carbonate from the bottom of the column (Patent Document 55),and a method in which alkylaryl carbonate is continuously supplied to amulti-stage distillation column and continuously reacted in the columnwhile removing produced low boiling point components including dialkylcarbonate by distillation and extracting generated products containingdiaryl carbonate from the bottom of the column (Patent Document 56).These methods are the first disclosures of efficient and continuousproduction of aromatic carbonate. Similar continuous production methodshave been thereafter filed, such as a method in which materials arebrought into contact in a column type reactor to performtransesterification (Patent Documents 57, 58 and 59), a method in whicha plurality of reaction vessels are connected in series (PatentDocuments 60 and 61), a method in which a bubble column reactor is used(Patent Document 62) and a method in which a vertical reaction vessel isused (Patent Document 63).

Regarding industrial production of aromatic carbonate by these methods,methods for stable and long-term operation have also been proposed.Patent Document 64 discloses a method in which aliphatic alcohol isremoved from a distillation column connected to a reactor so that theconcentration of the aliphatic alcohol in the reactor is 2% by weight orless upon production of aromatic carbonate from dialkyl carbonate and anaromatic hydroxy compound, and it is described that stable continuousoperation was achieved. The method of the publication is directed toavoid problems of precipitation of catalyst in the distillation column.Further, Patent Document 65 discloses a method which enables long-termstable operation by suppressing precipitation of catalyst by controllingthe weight ratio of an aromatic polyhydroxy compound and/or a residuethereof to 2 or less relative to the metal component of the catalyst ina liquid matter in the system containing the catalyst.

On the other hand, the catalyst used in this reaction system is usuallydissolved in a reaction mixture under reaction conditions, and has ahigher boiling point than aromatic carbonate. Therefore, to obtain highpurity aromatic carbonate from the reaction mixture, low boiling pointcomponents are first removed from the mixture and then diaryl carbonateof the high boiling point components is separated from the catalyst soas to purify the diaryl carbonate. It is known that the catalyst may berecovered and reused as a high boiling point component in that case, anddeactivated components may be removed. Examples of such method ofseparating catalyst are described in Patent Document 66.

Titanium compounds are known to be an excellent catalyst (e.g., PatentDocuments 67 and 68). However, when titanium based catalysts, forexample, titanium phenoxide: Ti(OPh)₄ or titanium alkoxide: Ti(OR)₄, isused, there is a problem that diaryl carbonate which is the finalproduct is colored with dark red as described in Patent Document 69.This is because, since titanium butoxide: Ti(OBu)₄ typically used has aboiling point of 206° C. at 1.3 KPa and titanium phenoxide typicallyused has a boiling point of about 250° C. at about 27 Pa (No patentDocument 1), they are also distilled off in a proportion correspondingto their vapor pressure upon separation of diaryl carbonate bydistillation and therefore not sufficiently separated from the product.Further, as described in Patent Document 70, degradation of catalyst anddeterioration of diaryl carbonate due to high temperature in separationof titanium phenoxide have been reported. Also, Patent Document 71describes a problem that when Ti(OPh)₄ is used and a mixture of startingmaterials and a catalyst is supplied to a continuous multi-stagedistillation column to continue the reaction, the distillation columnmay be clogged. Thus, the well-known titanium based catalysts haveproblems that due to their high vapor pressure under reactionconditions, separation of produced diaryl carbonate is difficult, andthe fraction at high temperature for a long period causes degradation ofcatalyst, clogging of the distillation column and deterioration ofdiaryl carbonate.

[Patent Document 1] JP-A-51-105032

[Patent Document 2] JP-A-56-123948

[Patent Document 3] JP-A-56-123949

[Patent Document 4] DE 2528412

[Patent Document 5] GB Patent No. 1499530

[Patent Document 6] U.S. Pat. No. 4,182,726

[Patent Document 7] JP-A-54-48733

[Patent Document 8] DE 2736062

[Patent Document 9] JP-A-54-63023

[Patent Document 10] JP-A-60-169444

[Patent Document 11] U.S. Pat. No. 4,554,110

[Patent Document 12] JP-A-60-169445

[Patent Document 13] U.S. Pat. No. 4,552,704

[Patent Document 14] JP-A-62-277345

[Patent Document 15] JP-A-1-265063

[Patent Document 16] JP-A-57-176932

[Patent Document 17] JP-A-57-183745

[Patent Document 18] JP-A-58-185536

[Patent Document 19] U.S. Pat. No. 4,410,464

[Patent Document 20] JP-A-60-173016

[Patent Document 21] U.S. Pat. No. 4,609,501

[Patent Document 22] JP-A-1-265064

[Patent Document 23] JP-A-61-172852

[Patent Document 24] JP-A-51-75044

[Patent Document 25] DE 2552907

[Patent Document 26] U.S. Pat. No. 4,045,464

[Patent Document 27] JP-A-60-169444

[Patent Document 28] U.S. Pat. No. 4,554,110

[Patent Document 29] JP-A-60-169445

[Patent Document 30] U.S. Pat. No. 4,552,704

[Patent Document 31] JP-A-60-173016

[Patent Document 32] U.S. Pat. No. 4,609,501

[Patent Document 33] JP-A-1-93560

[Patent Document 34] Japanese Patent No. 2540590

[Patent Document 35] JP-A-1-265063

[Patent Document 36] JP-A-1-265064

[Patent Document 37] JP-A-54-48732

[Patent Document 38] DE 736063

[Patent Document 39] U.S. Pat. No. 4,252,737

[Patent Document 40] JP-A-61-291545

[Patent Document 41] JP-A-58-185536

[Patent Document 42] U.S. Pat. No. 4,104,64

[Patent Document 43] JP-A-56-123948

[Patent Document 44] U.S. Pat. No. 4,182,726

[Patent Document 45] JP-A-56-25138

[Patent Document 46] JP-A-60-169444

[Patent Document 47] U.S. Pat. No. 4,554,110

[Patent Document 48] JP-A-60-169445

[Patent Document 49] U.S. Pat. No. 4,552,704

[Patent Document 50] JP-A-60-173016

[Patent Document 51] U.S. Pat. No. 4,609,501

[Patent Document 52] Examples of JP-A-61-172852

[Patent Document 53] Examples of JP-A-61-291545

[Patent Document 54] JP-A-62-277345

[Patent Document 55] JP-A-3-291257

[Patent Document 56] JP-A-4-9358

[Patent Document 57] JP-A-6-41022

[Patent Document 58] JP-A-6-157424

[Patent Document 59] JP-A-6-184058

[Patent Document 60] JP-A-6-234707

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[Patent Document 63] JP-A-6-345697

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[Patent Document 65] National Publication of International PatentApplication No. 9-11049

[Patent Document 66] JP-A-9-169704

[Patent Document 67] DE Patent No. 2,528,412

[Patent Document 68] DE Patent No. 2,552,907

[Patent Document 69] EP Patent No. 879

[Patent Document 70] JP-A-9-169704

[Patent Document 71] JP-A-2004-307400

[Non-patent Document 1] J. Inorg. Nucl. Chem. Vol. 28, 2410 (1966)

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

An object of the present invention is to provide a method of producinghigh purity diaryl carbonate in which a catalyst can be easily separatedwithout the above-described problems, when producing an aromaticcarbonate by allowing to react a starting material selected from thegroup consisting of a dialkyl carbonate, an alkylaryl carbonate and amixture thereof and a reactant selected from the group consisting of anaromatic monohydroxy compound, an alkylaryl carbonate and a mixturethereof in the presence of a metal-containing catalyst, with distillingoff by-product alcohol and/or by-product dialkyl carbonate to theoutside of the reaction system.

Means for Solving the Problems

As a result of intensive studies conducted by the present inventors tosolve the aforementioned problems, the inventors have found that theobject can be achieved by using a specific metal-containing catalyst asa catalyst when producing an aromatic carbonate by allowing to react astarting material selected from the group consisting of a dialkylcarbonate, an alkylaryl carbonate and a mixture thereof with a reactantselected from the group consisting of an aromatic monohydroxy compound,an alkylaryl carbonate and a mixture thereof in the presence of ametal-containing catalyst, with distilling off by-product alcohol and/orby-product dialkyl carbonate to the outside of the reaction system, andthe present invention has been completed. Surprisingly, the presentinvention can solve the problem of conventional method that clogging andblocking of distillation column frequently occur when reactants and acatalyst are supplied to the middle plate of the distillation column,and the present invention also makes it easier to separate produceddiaryl carbonate from other components and thus can produce high puritydiaryl carbonate in which the amount mixed of a metal compound derivedfrom a catalyst is extremely small.

Accordingly, the present invention is as follows.

[1] A method for producing an aromatic carbonate, which comprisesallowing to react a starting material selected from the group consistingof a dialkyl carbonate represented by the following formula (1), analkylaryl carbonate represented by the following formula (2) and amixture thereof with a reactant selected from the group consisting of anaromatic monohydroxy compound represented by the following formula (3),an alkylaryl carbonate represented by the following formula (4) and amixture thereof in the presence of a metal-containing catalyst, withdistilling off by-product alcohols and/or by-product dialkyl carbonatesto the outside of the reaction system, thereby producing an aromaticcarbonate represented by the following formula (5) and/or the followingformula (6) corresponding to the starting material and the reactant,wherein the metal-containing catalyst has a molecular weight of 450 ormore and is dissolved in a liquid phase in the reaction system orpresent in the form of liquid during the reaction,

(wherein R¹, R² and R³ in the formulas (1) to (4) independentlyrepresent an alkyl group having 1 to 10 carbon atoms, an alicyclic grouphaving 3 to 10 carbon atoms or an aralkyl group having 6 to 10 carbonatoms, and Ar¹, Ar² and Ar³ independently represent an aromatic grouphaving 5 to 30 carbon atoms), and

(wherein R and Ar in the formulas (5) and (6) are each selected from R¹,R², R³, Ar¹, Ar² and Ar³ of the corresponding starting material andreactant).

[2] The method according to [1], wherein the metal-containing catalystis a molecular weight of 480 or more.

[3] The method according to [1], wherein the metal-containing catalystis a titanium containing compound.

[4] The method according to [3], wherein the titanium containingcompound is an organic polytitanoxane composition.

[5] The method according to [4], wherein the organic polytitanoxanecomposition contains at least one alkoxy group and/or aryloxy group asan organic group.

[6] The method according to [4], wherein the organic polytitanoxanecomposition is obtained by a polycondensation reaction of at least oneraw material selected from the group consisting of tetraalkoxytitanium,tetrahalotitanium (TiX₄:X being selected from Cl and Br) and titaniumhydroxide.

[7] The method according to [6], wherein the organic polytitanoxanecomposition is obtained by sequentially or simultaneously performing thetwo steps of:

1) preparing a partially hydrolyzed product by partially hydrolyzingtetraalkoxytitanium and

2) distilling off a generated low boiling point component includingalcohol from the partially hydrolyzed product and subjecting the productto polycondensation.

[8] The method according to [6], wherein the organic polytitanoxanecomposition is obtained by subjecting tetraalkoxytitanium to heating,deetherification and polycondensation.

[9] The method according to [6], wherein the organic polytitanoxanecomposition is obtained by sequentially or simultaneously performing thethree steps of:

1) preparing a partially hydrolyzed product by partially hydrolyzingtetrahalotitanium,

2) distilling off a low boiling point component from the partiallyhydrolyzed product and subjecting the product to polycondensation and

3) reacting the resultant with alcohol, removing HX therefrom andalkoxylating the same.

[10] The method according to any one of [4] to [9], wherein thepolytitanoxane composition is used as is or after alkoxy group exchangeby reacting the composition with a composition containing at least onemember selected from alcohol, an aromatic hydroxy compound and carbonicacid ester.

[11] The method according to any one of [4] to [10], wherein thetitanium containing compound contains at least two Ti atoms in onemolecule.

[12] The method according to [11], wherein the titanium containingcompound contains 2 to 6 Ti atoms in one molecule.

[13] The method according to [11], wherein the titanium containingcompound contains at least one Ti—O—Ti bond in a molecule.

[14] The method according to [1], wherein the metal-containing catalysthas a vapor pressure at 230° C. of 10 Pa or lower.

[15] The method according to any one of [1] to [14], wherein themetal-containing catalyst is used in a proportion of 0.0001 to 30% byweight based on the total weight of the starting material and thereactant.

[16] The method according to any one of [1] to [15], wherein thearomatic hydroxy compound is phenol.

[17] Diphenyl carbonate produced by the method according to [16]containing 1 ppm or less of a metal component derived from themetal-containing catalyst.

[18] Polycarbonate comprising the diphenyl carbonate produced by themethod according to [16] containing 1 ppm or less of a metal componentderived from the metal-containing catalyst.

Although titanium-based catalysts have excellent catalytic actionincluding a good reaction rate and selectivity as described above, itwas difficult to separate such titanium catalyst or a titaniumcontaining compound derived from the titanium catalyst from produceddiaryl carbonate in the reaction mixture after the reaction and toobtain diaryl carbonate whose titanium content is small. A novel findingthat use of a specific titanium catalyst facilitates separation has madeit possible for the first time to obtain diaryl carbonate whose titaniumcontent is small without difficulty.

According to the present invention, diaryl carbonate whose titaniumcontent is small can be easily produced without causing problems such ascoloring due to titanium.

In the following, the present invention is described in detail. Thedialkyl carbonate used in the present invention is represented by theformula (1):

wherein R¹ represents an alkyl group having 1 to 10 carbon atoms, analicyclic group having 3 to 10 carbon atoms or an aralkyl group having 6to 10 carbon atoms.

Examples of dialkyl carbonates containing such R¹ include dimethylcarbonate, diethyl carbonate, dipropyl carbonate (and isomers thereof),dibutenyl carbonate (and isomers thereof), dibutyl carbonate (andisomers thereof), dipentyl carbonate (and isomers thereof), dihexylcarbonate (and isomers thereof), diheptyl carbonate (and isomersthereof), dioctyl carbonate (and isomers thereof), dinonyl carbonate(and isomers thereof), didecyl carbonate (and isomers thereof),dicyclopentyl carbonate, dicyclohexyl carbonate, dicycloheptylcarbonate, dibenzyl carbonate, diphenetyl carbonate (and isomersthereof), di(phenylpropyl) carbonate (and isomers thereof),di(phenylbutyl) carbonate (and isomers thereof), di(chlorobenzyl)carbonate (and isomers thereof), di(methoxybenzyl) carbonate (andisomers thereof), di(methoxymethyl) carbonate, di(methoxyethyl)carbonate (and isomers thereof), di(chloroethyl) carbonate (and isomersthereof) and di(cyanoethyl) carbonate (and isomers thereof). Of thesedialkyl carbonates, those in which R¹ contains an alkyl group having 1to 6 carbon atoms are preferably used in the present invention. R¹ ismore preferably an n-butyl group, an isobutyl group and an alkyl grouphaving 5 or 6 carbon atoms, and dialkyl carbonate containing a linear orbranched alkyl group in which the carbon atom at the α position ofoxygen is secondary carbon (—CH₂—) is preferred. Particularly preferredare dibutyl carbonate and bis (2-ethylbutyl) carbonate.

The alkylaryl carbonate used as a starting material in the presentinvention is represented by the formula (2):

wherein R² may be the same as or different from R¹ and represents analkyl group having 1 to 10 carbon atoms, an alicyclic group having 3 to10 carbon atoms or an aralkyl group having 6 to 10 carbon atoms, and Ar²represents an aromatic group having 5 to 30 carbon atoms.

Examples of such R² are groups listed above as R¹. Examples of Ar²include phenyl, tolyl (and isomers thereof), xylyl (and isomersthereof), alkylphenyls groups such as trimethylphenyl (and isomersthereof), tetramethylphenyl (and isomers thereof), ethylphenyl (andisomers thereof), propylphenyl (and isomers thereof), butylphenyl (andisomers thereof), diethylphenyl (and isomers thereof), methylethylphenyl(and isomers thereof), pentylphenyl (and isomers thereof), hexylphenyl(and isomers thereof) and cyclohexylphenyl (and isomers thereof);alkoxyphenyl groups such as methoxyphenyl (and isomers thereof),ethoxyphenyl (and isomers thereof) and buthoxyphenyl (and isomersthereof); halogenated phenyl groups such as fluorophenyl (and isomersthereof), chlorophenyl (and isomers thereof), bromophenyl (and isomersthereof), chloro(methyl)phenyl (and isomers thereof) and dichlorophenyl(and isomers thereof); substituted phenyl groups represented by thefollowing formula (7):

(wherein A represents a bond, a divalent group such as —O—, —S—, —CO— or—SO₂—, an alkylene group or a substituted alkylene group represented bythe following (8) or a cycloalkylene group represented by the following(9), and an aromatic ring may be substituted by a lower alkyl group, alower alkoxy group, an ester group, a hydroxy group, a nitro group, ahalogen or a cyano group),

wherein R⁴, R⁵, R⁶ and R⁷ are each independently a hydrogen atom, alower alkyl group, a cycloalkyl group, an aryl group or an aralkylgroup, which may be optionally substituted by a halogen atom or analkoxy group, and

(wherein k is an integer of 3 to 11 and a hydrogen atom may besubstituted by a lower alkyl group, an aryl group or a halogen atom);naphthyl (and isomers thereof), substituted naphthyl groups such asmethylnaphthyl (and isomers thereof), dimethylnaphthyl (and isomersthereof), chloronaphthyl (and isomers thereof), methoxynaphthyl (andisomers thereof) and cyanonaphthyl (and isomers thereof); andsubstituted or unsubstituted heteroaromatic groups such as pyridine (andisomers thereof), cumaryl (and isomers thereof), quinolyl (and isomersthereof), methylpyridyl (and isomers thereof), chloropyridyl (andisomers thereof), methylcumaryl (and isomers thereof) and methylquinolyl(and isomers thereof).

Examples of alkylaryl carbonates containing such R² and Ar² includemethyl phenyl carbonate, ethyl phenyl carbonate, propyl phenyl carbonate(and isomers thereof), allyl phenyl carbonate, butyl phenyl carbonate(and isomers thereof), pentyl phenyl carbonate (and isomers thereof),hexyl phenyl carbonate (and isomers thereof), heptyl phenyl carbonate(and isomers thereof), octyl tolyl carbonate (and isomers thereof),nonyl (ethylphenyl) carbonate (and isomers thereof), decyl (butylphenyl)carbonate (and isomers thereof), methyl tolyl carbonate (and isomersthereof), ethyl tolyl carbonate (and isomers thereof), propyl tolylcarbonate (and isomers thereof), butyl tolyl carbonate (and isomersthereof), allyl tolyl carbonate (and isomers thereof), methyl xylylcarbonate (and isomers thereof), methyl (trimethylphenyl) carbonate (andisomers thereof), methyl (chlorophenyl) carbonate (and isomers thereof),methyl (nitrophenyl) carbonate (and isomers thereof), methyl(methoxyphenyl) carbonate (and isomers thereof), methyl cumyl carbonate(and isomers thereof), methyl (naphthyl) carbonate (and isomersthereof), methyl (pyridyl) carbonate (and isomers thereof), ethyl cumylcarbonate (and isomers thereof), methyl (benzoyl phenyl) carbonate (andisomers thereof), ethyl xylyl carbonate (and isomers thereof) and benzylxylyl carbonate.

Of these alkylaryl carbonates, those in which R² is an alkyl grouphaving 1 to 6 carbon atoms, and more preferably R¹ is n-butyl, isobutylor an alkyl group having 5 to 6 carbon atoms and Ar² is an aromaticgroup having 6 to 10 carbon atoms are more preferably used. Particularlypreferred are butyl phenyl carbonate and (2-ethylbutyl)phenyl carbonate.The starting material used in the present invention is selected from thegroup consisting of a dialkyl carbonate represented by theabove-described formula (1), an alkylaryl carbonate represented by theformula (2) and a mixture thereof.

The aromatic monohydroxy compound used as a reactant in the presentinvention is represented by the following formula (3), and any compoundmay be used as long as a hydroxyl group is directly bonded to thearomatic group.Ar¹OH  (3)

In the formula, Ar¹ may be the same as or different from Ar² andrepresents an aromatic group having 5 to 30 carbon atoms. Examples ofsuch Ar¹ are those listed above as Ar².

Examples of aromatic monohydroxy compounds having such Ar¹ includephenol, alkylphenols such as cresol (and isomers thereof), xylenol (andisomers thereof), trimethylphenol (and isomers thereof),tetramethylphenol (and isomers thereof), ethylphenol (and isomersthereof), propylphenol (and isomers thereof), butylphenol (and isomersthereof), diethylphenol (and isomers thereof), methylethylphenol (andisomers thereof), methylpropylphenol (and isomers thereof),dipropylphenol (and isomers thereof), methylbutylphenol (and isomersthereof), pentylphenol (and isomers thereof), hexylphenol (and isomersthereof) and cyclohexylphenol (and isomers thereof); alkoxyphenols suchas methoxyphenol (and isomers thereof) and ethoxyphenol (and isomersthereof); substituted phenols represented by the formula (10):

(wherein A is a group as defined above); naphthol (and isomers thereof)and substituted naphthols; and monohydroxy heteroaromatic compounds suchas hydroxypyridine (and isomers thereof), hydroxycoumarin (and isomersthereof) and hydroxyquinoline (and isomers thereof). Of these aromaticmono hydroxy compounds, aromatic mono hydroxy compounds whose Ar¹ is anaromatic group having 6 to 10 carbon atoms are preferred in the presentinvention, and phenol is particularly preferred.

The alkylaryl carbonate used as a reactant in the present invention isrepresented by the following formula (4).

In the formula, R³ may be the same as or different from R¹ and R², andrepresents an alkyl group having 1 to 10 carbon atoms, an alicyclicgroup having 3 to 10 carbon atoms or an aralkyl group having 6 to 10carbon atoms, and Ar³ may be the same as or different from Ar¹ and Ar²,and represents an aromatic group having 5 to 30 carbon atoms. Examplesof such R³ are groups listed above as R¹, and examples of Ar³ are thoselisted above as Ar².

Examples of alkylaryl carbonates containing such R³ and Ar³ are thoselisted above as in the formula (2). Of these alkylaryl carbonates, thosewhose R³ has an alkyl group having 1 to 6 carbon atoms and Ar³ is anaromatic group having 6 to 10 carbon atoms are preferably used. R³ ismore preferably an n-butyl group, an isobutyl group or a linear orbranched alkyl group having 5 to 6 carbon atoms in which the carbon atomat the α position of oxygen is secondary carbon (—CH₂—). Particularlypreferred are butyl phenyl carbonate and (2-ethylbutyl) phenylcarbonate.

The reactant of the present invention is selected from the groupconsisting of an aromatic monohydroxy compound represented by theformula (3), an alkylaryl carbonate represented by the formula (4) and amixture thereof. The method of the present invention for producing anaromatic carbonate or an aromatic carbonate mixture, which comprisesallowing to react a starting material and a reactant in the presence ofa metal-containing catalyst typically involves the reactions of theformulas (E1), (E2), (E3) and (E4).

(In the formulas, R¹, R², R³, Ar¹, Ar² and Ar³ are as defined above; inthe reaction formula (E4), Ar independently represents Ar² or Ar³ and Rindependently represents R² or R³; when R²═R³ and Ar²═Ar³ in thereaction formula (E4), the reaction is an transesterification betweenthe same kind of molecules, which may also be generally referred to as adisproportionation reaction.)

When carrying out reactions of the formulas (E1), (E2), (E3) and (E4)according to the method of the present invention, one or at least twodialkyl carbonates and alkylaryl carbonates may be used as startingmaterials. Further, one or at least two aromatic monohydroxy compoundsand alkylaryl carbonates may be used as reactants.

A case in which R²═R³═R and Ar²═Ar³═Ar in the transesterificationrepresented by the reaction formula (E4) is preferred because diarylcarbonate and dialkyl carbonate are obtained by an transesterificationof the same kind of molecules of one alkylaryl carbonate. Further, whenR¹═R²═R³═R and Ar¹═Ar²═Ar³═Ar in the reaction formulas (E1) and (E4),diaryl carbonate is obtained from dialkyl carbonate and an aromaticmonohydroxy compound through alkylaryl carbonate as described in thefollowing reaction formulas (E5) and (E6) by combining the reactionrepresented by the reaction formula (E1) and the reaction represented bythe reaction formula (E4), and this is a particularly preferredembodiment of the present invention.

When dialkyl carbonate produced as a by-product in the reactionrepresented by the reaction formula (E6) is reused as a raw material ofthe reaction represented by the reaction formula (E5), 1 mole of diarylcarbonate and 2 moles of aliphatic alcohol are produced from 1 mole ofdialkyl carbonate and 2 moles of an aromatic monohydroxy compound. Inthe above-described reaction formula (E5), when R is selected fromn-butyl, iso-butyl and an alkyl group having 5 to 6 carbon atoms andAr═C₆H₅, by-product alcohol has the lowest boiling point in the reactionsystem and forms no azeotrope with dialkyl carbonate which is areactant. This case is particularly advantageous because the reactionproceeds efficiently and easily produces diphenyl carbonate which is animportant raw material of polycarbonate and isocyanate.

The metal-containing catalyst used in the present invention means aspecific metal-containing catalyst which facilitates the aforementionedreactions of the reaction formulas (E1) to (E4), has a molecular weightof 450 or more, more preferably a molecular weight of 480 or more, andis in the form of liquid (under the above-described reaction conditions)or dissolved in the liquid phase of the reaction system. Themetal-containing catalyst is preferably a titanium containing compoundcontaining titanium. Examples of preferred titanium containing compoundsin the form of liquid under the above-described reaction conditions ordissolved in the liquid phase of the reaction system includeorganopolytitanoxane composition such as polyorthotitanate and condensedorthotitanate. It is preferred that the organic polytitanoxane has atleast one alkoxy group and/or aryloxy group as an organic group.

When the metal-containing catalyst is a metal-containing catalystcontaining titanium and/or a metal-containing catalyst having a vaporpressure at 230° C. of 10 Pa or lower and containing titanium, thecatalyst preferably contains at least two Ti atoms in one molecule, morepreferably 2 to 6 Ti atoms in one molecule. When the metal-containingcatalyst contains 2 or more Ti atoms in one molecule, the compoundcontains at least one Ti—O—Ti bond in one molecule. When themetal-containing catalyst contains Sn, it contains at least 3 Sn atoms.

Examples of such compounds include metal-containing catalystsrepresented by the following formulas (11), (12) and (13), titanateoligomers containing at least one titanoxane structure (Ti—O—Ti bond)(e.g., titanium compounds represented by the following formula (14)) inone molecule and tin compounds represented by the following formula(15). Since the above-described metal-containing catalysts are easilyassociated, they may be in the form of a monomer, in an associated form,or an adduct or an associated form with alcohol or an aromatic hydroxycompound. These catalytic components may be a product of a reaction withan organic compound present in the reaction system, e.g., aliphaticalcohols, an aromatic monohydroxy compounds, alkylaryl carbonates,diaryl carbonates or dialkyl carbonates, or may be heated in the form ofa raw material or a product prior to the reaction. The titanium compoundrepresented by the formula (11) and/or the formula (14) (e.g., when R⁴⁴to R⁶¹ in the formula (14) are aromatic groups (e.g., phenyl group))tends to form an adduct particularly with an aromatic hydroxy compound.The structure of the adduct is unknown by the present analyticalmethods, but the structure represented by the following formula has amolecular weight of 450 or more, more preferably a molecular weight of480 or more, excluding the molecular weight of the molecules involved inthe formation of an adduct. Such molecules involved in the formation ofan adduct may be identified by a method such as NMR, or the aromatichydroxy compound involved in the formation of an adduct may be removedby a known method (e.g., recrystallization using solvent described in J.Indian. Chem. Soc., Vol. 38, No. 3, 147-152 (1961)).

In the formula (11), R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷,R¹⁸, R¹⁹, R²⁰, R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, and R²⁷ independentlyrepresent a hydrogen atom, an alkyl group, an aralkyl group or an arylgroup, X₁ and X₂ represent an alkyl group, an aralkyl group or an arylgroup; R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰,R²¹, R²², R²³, R²⁴, R²⁵, R²⁶ and R²⁷ are not simultaneously a hydrogenatom, and at least four of them are an alkyl group, an aralkyl group oran aryl group; R²⁸, R²⁹, R³⁰, R³¹, R³², R³³, R³⁴ and R³⁵ may becovalently bonded within the range that the molecular weight is 450 ormore, and more preferably 480 or more)

(In the formula (12), R²⁸, R²⁹, R³⁰, R³¹, R³², R³³, R³⁴ and R³⁵independently represent a hydrogen atom, an alkyl group, an aralkylgroup or an aryl group; X₁ and X₂ represent an alkyl group, an aralkylgroup and an aryl group; at least two of R²⁸, R²⁹, R³⁰, R³¹, R³², R³³,R³⁴, R³⁵, X₁ and X₂ are an aralkyl group or an aryl group.)

(In the formula (13), R³⁶, R³⁷, R³⁸, R³⁹, R⁴⁰, R⁴¹, R⁴² and R⁴³independently represent a hydrogen atom, an alkyl group, an aralkylgroup or an aryl group, at least two of them are an aralkyl group or anaryl group, and these R³⁶ to R⁴³ may be bonded with each other.)

(In the formula (14), R⁴⁴, R⁴⁵, R⁴⁶, R⁴⁷, R⁴⁸, R⁴⁹, R⁵⁰, R⁵¹, R⁵², R⁵³,R⁵⁴, R⁵⁵, R⁵⁶, R⁵⁷, R⁵⁸, R⁵⁹, R⁶⁰, and R⁶¹ independently represent ahydrogen atom, an alkyl group, an aralkyl group, an aryl group or anacyl group, a, b, c, d, e and f independently represent an integer of 0to 4, and R⁴⁴, R⁴⁵, R⁴⁶, R⁴⁷, R⁴⁸, R⁴⁹, R⁵⁰, R⁵¹, R⁵², R⁵³, R⁵⁴, R⁵⁵,R⁵⁶, R⁵⁷, R⁵⁸, R⁵⁹, R⁶⁰ and R⁶¹ in the formula (14) each may becovalently bonded.)

(In the formula (15), R⁶² is an alkyl group, an aralkyl group or an arylgroup having 4 or more carbon atoms, R⁶³, R⁶⁴, R⁶⁵, R⁶⁶ and R⁶⁷independently represent a hydrogen atom, an alkyl group, an aralkylgroup, an aryl group or an acyl group, g represents an integer of 1 ormore, and R⁶³, R⁶⁴, R⁶⁵, R⁶⁶ and R⁶⁷ in the formula (15) each may becovalently bonded.)

Examples of alkyl groups represented by R⁸ to R⁶¹ include linear orcyclic alkyl groups having 1 to 10 carbon atoms, such as a methyl group,an ethyl group, a propyl group (and isomers thereof), a butyl group (andisomers thereof), a pentyl group (and isomers thereof), a hexyl group(and isomers thereof), a heptyl group (and isomers thereof), an octylgroup (and isomers thereof), a nonyl group (and isomers thereof), adecyl group (and isomers thereof), a cyclobutyl group, a cyclopentylgroup (and isomers thereof) and a cyclohexyl group (and isomersthereof). Those containing an ether bond are also useful, and examplesthereof include a methoxyethyl group (and isomers thereof), anethoxyethyl group (and isomers thereof), a methoxypropyl group (andisomers thereof), an ethoxypropyl group (and isomers thereof), amethoxybutyl group (and isomers thereof) and an ethoxybutyl group (andisomers thereof).

Examples of aralkyl groups represented by R⁸ to R⁶¹ include aralkylgroups having 7 to 12 carbon atoms which may have a substituent, such asa benzyl group and a phenylethyl group.

Examples of aryl groups represented by R⁸ to R⁶¹ include phenyl oralkylphenyl groups such as phenyl, tolyl (and isomers thereof), xylyl(and isomers thereof), trimethylphenyl (and isomers thereof),tetramethylphenyl (and isomers thereof), ethylphenyl (and isomersthereof), propylphenyl (and isomers thereof), butylphenyl (and isomersthereof), diethylphenyl (and isomers thereof), methylethylphenyl (andisomers thereof), pentylphenyl (and isomers thereof), hexylphenyl (andisomers thereof) and cyclohexylphenyl (and isomers thereof);alkoxyphenyl groups such as methoxyphenyl (and isomers thereof),ethoxyphenyl (and isomers thereof) and butoxyphenyl (and isomersthereof); halogenated phenyl groups such as fluorophenyl (and isomersthereof), chlorophenyl (and isomers thereof), bromophenyl (and isomersthereof), chloro(methyl)phenyl (and isomers thereof) and dichlorophenyl(and isomers thereof); substituted phenyl groups represented by thefollowing formula (16):

(wherein B represents a bond, a divalent group such as —O—, —S—, —CO—and —SO₂—, an alkylene group or a substituted alkylene group representedby the following (17) or a cycloalkylene group represented by thefollowing (18), and an aromatic ring may be substituted by a lower alkylgroup, a lower alkoxy group, an ester group, a hydroxy group, a nitrogroup, a halogen or a cyano group),

(wherein R⁶⁸, R⁶⁹, R⁷⁰ and R⁷¹ are each independently a hydrogen atom, alower alkyl group, a cycloalkyl group, an aryl group or an aralkylgroup, which may be optionally substituted by a halogen atom or analkoxy group), and

(wherein m is an integer of 3 to 11 and a hydrogen atom may besubstituted by a lower alkyl group, an aryl group or a halogen atom);naphthyl (and isomers thereof), substituted naphthyl groups such asmethylnaphthyl (and isomers thereof), dimethylnaphthyl (and isomersthereof), chloronaphthyl (and isomers thereof), methoxynaphthyl (andisomers thereof) and cyanonaphthyl (and isomers thereof); andsubstituted or unsubstituted heteroaromatic groups such as pyridine (andisomers thereof), cumaryl (and isomers thereof), quinolyl (and isomersthereof), methylpyridyl (and isomers thereof), chloropyridyl (andisomers thereof), methylcumaryl (and isomers thereof) and methylquinolyl(and isomers thereof).

The aryl group represented by R⁸ to R⁶¹ may also be a hydroxysubstituted aryl group which is represented by the following formula(19):Ar⁴—(OH)_(n)  (19)(wherein Ar⁴ represent an aromatic group having a valence of n, n is aninteger of 2 or more, and each —OH group may be bonded to any positionof Ar⁴).

The residue of the aromatic polyhydroxy compound is represented by thefollowing formula (20) and is chemically bonded to at least one memberselected from the group consisting of metal of metal-containingcatalyst, an alkoxycarbonyl group derived from dialkyl carbonate oralkylaryl carbonate, an aryloxycarbonyl group derived from alkylarylcarbonate or diaryl carbonate and a carbonyl group derived from dialkylcarbonate, alkylaryl carbonate or diaryl carbonate,—(O)_(n)—Ar⁴—(OH)_(n-p)  (20)(wherein Ar⁴ and n are as described above, p is an integer of 1 to m,and an —OH group and an —O— group may be bonded to any position of thearomatic ring of Ar⁴)

Examples of Ar⁴ in the formula (19) and (20) include aromatic groupsrepresented by the following formulas (21), (22), (23), (24) and (25):

(wherein Q¹ is a single bond, a divalent alkylene group having 1 to 30carbon atoms or a divalent group selected from —O—, —CO—, —S—, —SO₂—,—SO— and —COO—);

(wherein Q¹ is as defined above and each Q¹ may be the same ordifferent); and

(wherein Q² represents a tri-valent group such as a tri-valentalkanetriyl group having 1 to 30 carbon atoms or a tri-valent aromaticgroup; at least one hydrogen atom on an aromatic ring may be substitutedby another substituent such as a halogen atom, an alkoxy group having 1to 30 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, acyano group, an ester group, an amide group or a nitro group).

Examples of such hydroxy substituted aryl groups include hydroxyphenyl(and isomers thereof), dihydroxyphenyl (and isomers thereof),trihydroxyphenyl (and isomers thereof), hydroxytolyl (and isomersthereof), hydroxyxylyl (and isomers thereof),[1-(hydroxyphenyl)-1-methyl-ethyl]-phenyl (and isomers thereof),[4-(hydroxybenzyl)]-phenyl (and isomers thereof),(hydroxy-phenoxy)-phenyl (and isomers thereof), hydroxybenzoyl-phenyl(and isomers thereof), hydroxybiphenyl (and isomers thereof),2-(hydroxyphenyl)-hydroxypropyl-phenyl, tri-(hydroxyphenyl)-phenyl (andisomers thereof), hydroxynaphthyl (and isomers thereof) andtrihydroxynaphthyl (and isomers thereof).

Examples of acyl groups include acyl groups represented by the followingformula (26):

(wherein Ar⁵ represents an aromatic group).

Examples of aromatic group represented by Ar⁵ include phenyl oralkylphenyl groups such as phenyl, tolyl (and isomers thereof), xylyl(and isomers thereof), trimethylphenyl (and isomers thereof),tetramethylphenyl (and isomers thereof), ethylphenyl (and isomersthereof), propylphenyl (and isomers thereof), butylphenyl (and isomersthereof), diethylphenyl (and isomers thereof), methylethylphenyl (andisomers thereof), pentylphenyl (and isomers thereof), hexylphenyl (andisomers thereof) and cyclohexyl phenyl (and isomers thereof);alkoxyphenyl groups such as methoxyphenyl (and isomers thereof),ethoxyphenyl (and isomers thereof) and butoxyphenyl (and isomersthereof); halogenated phenyl groups such as fluorophenyl (and isomersthereof), chlorophenyl (and isomers thereof), bromophenyl (and isomersthereof), chloro(methyl)phenyl (and isomers thereof) and dichlorophenyl(and isomers thereof) and substituted phenyl groups represented by theaforementioned formulas (16), (19) and (20).

Examples of such acyl groups include a benzoyl group, a phthaloyl group,a terephthaloyl group and a salicyl group.

The same kinds of groups as those selected from R¹, R², R³, Ar¹, Ar² andAr³ of the starting material and/or the reactant are preferred as thegroups of R⁴⁴˜R⁶¹ because kinds of products can be reduced. In case ofthe compound represented by formula (11), they are R⁸˜R²⁷ when themolecular weight of the compound is 450 or more, and more preferably 480or more. In case of the compound represented by formula (14), the groupsof R⁴⁴˜R⁶¹ are selected so that the molecular weight of the compound is450 or more, and more preferably 480 or more.

Examples of alkyl groups represented by R⁶² in the formula (15) includea linear or cyclic alkyl group having 4 to 10 carbon atoms such as abutyl group (and isomers thereof), a penthyl group (and isomersthereof), a hexyl group (and isomers thereof), a heptyl group (andisomers thereof), an octyl group (and isomers thereof), a nonyl group(and isomers thereof), a decyl group (and isomers thereof), a cyclobutylgroup, a cyclopentyl group (and isomers thereof) and a cyclohexyl group(and isomers thereof). Those containing an ether bond are also useful,and examples thereof include a methoxyethyl group (and isomers thereof),an ethoxyethyl group (and isomers thereof), a methoxypropyl group (andisomers thereof), an ethoxypropyl group (and isomers thereof), amethoxybutyl group (and isomers thereof) and an ethoxybutyl group (andisomers thereof).

Examples of aralkyl groups represented by R⁶² include aralkyl groupshaving 7 to 12 carbon atoms which may have a substituent, such as abenzyl group and a phenylethyl group.

Examples of aryl groups represented by R⁶² include phenyl or alkylphenylgroups such as phenyl, tolyl (and isomers thereof), xylyl (and isomersthereof), trimethylphenyl (and isomers thereof), tetramethylphenyl (andisomers thereof), ethylphenyl (and isomers thereof), propylphenyl (andisomers thereof), butylphenyl (and isomers thereof), diethylphenyl (andisomers thereof), methylethylphenyl (and isomers thereof), pentylphenyl(and isomers thereof), hexylphenyl (and isomers thereof) andcyclohexylphenyl (and isomers thereof); alkoxyphenyl groups such asmethoxyphenyl (and isomers thereof), ethoxyphenyl (and isomers thereof)and butoxyphenyl (and isomers thereof); halogenated phenyl groups suchas fluorophenyl (and isomers thereof), chlorophenyl (and isomersthereof), bromophenyl (and isomers thereof), chloro(methyl)phenyl (andisomers thereof) and dichlorophenyl (and isomers thereof).

Examples of R⁶³ to R⁶⁷ in the formula (15) include alkyl groups, aralkylgroups and aryl groups listed above as examples of R⁸ to R⁶¹.

The same kinds of groups as those selected from R¹, R², R³, Ar¹, Ar² andAr³ of the starting material and/or the reactant are preferred becausekinds of products can be reduced.

Examples of compounds represented by the formula (11) include titaniummethylphenoxide: Ti(OPhMe)₄ and titanium dimethylphenoxide:Ti(OPh(Me)₂)₄.

The compound represented by the formula (12) has a valence of Ti of 4,and the compound may contain alcohol or aromatic alcohol as a ligand inthe form of alcoholate or phenolate. Examples of compounds of theformula (12) include compounds of the following formula (27).

Examples of compounds represented by the formula (13) includetitanium-disalicylate, titanium-bis(2-methyl salicylate) andtitanium-bis(3-methyl salicylate).

Of the titanium containing compounds, an organic polytitanoxanecomposition produced by a known method may be used. Such known methodsinclude a method in which titanium alkoxide is partially hydrolyzed andsubjected to polycondensation while removing alcohol (e.g., Journal ofPolymer Science, vol. VII, No. 6, 591-602). Examples of suchpolytitanoxane compositions also include ladder polytitanoxane obtainedby the method described in JP-A-1-129031 and cyclic titanoxane obtainedby the method described in JP-A-1-31793, JP-A-1-52786 and JP-A-64-52786.

Further, a copolymer with another metal alkoxide obtained by the methoddescribed in JP-B-5-31900 may be also used. Polytitanoxane orcopolytitanoxane having 2 or more, preferably 2 to 6, more preferably 4to 6 Ti atoms in a molecule is preferably used. These polytitanoxane andcopolytitanoxane may contain at least one Ti—O—Ti bond in a molecule.Although analysis of Ti—O—Ti bonds is extremely difficult, researchersin this field now consider that a Ti—O—Ti bond is formed when titaniumalkoxide described above is partially hydrolyzed and subjected topolycondensation with removing alcohol, and the present invention alsofollows this argument. Specifically, as shown in the following formula(28), one Ti—O—Ti bond is formed by partially hydrolyzingtitanium(tetraalkoxide) by adding one molecule of water per twomolecules of titanium(tetraalkoxide) and then removing two molecules ofalcohol.

Further, in the case of a oligomerization reaction, polytitanoxanehaving a few Ti—O—Ti bonds in a molecule can be obtained by adding waterin an amount suitable for the oligomerization degree and removingproduced alcohol. In order to obtain a titanium compound containing 2 to6 Ti atoms in a molecule, tetraalkoxytitanium is partially hydrolyzed bywater of not more than 0.1 to 2-fold mole in a molar ratio relative toTi atoms, preferably by water of not more than 0.3 to 1.5-fold mole,more preferably by water of not more than 0.5 to 1.2-fold mole in orderto avoid generation of solid components caused by excessive partialhydrolysis; and then can be obtained by the polycondensation whichremoves low boiling point components. The amount of water used forpartial hydrolysis described above is based on the total amount oftetraalkoxytitanium used for producing an organic polytitanoxanecomposition. All of water necessary for partial hydrolysis may be usedfor partial hydrolysis of part of the tetraalkoxytitanium used forproduction, and then the rest of the tetraalkoxytitanium is addedthereto to perform a reaction. In this case, an organic polytitanoxanecomposition containing many branched structures can be obtained. Solidcomponents generated during partial hydrolysis may be removed byfiltration. Referring to the partial hydrolysis, tetraalkoxytitanium isdissolved in an alcohol solvent and the solution is cooled to 80° C. orlower, preferably 5° C. or lower, then alcohol containing a desiredamount of water is added thereto dropwise over 1 to 5 hours understirring, the solution temperature is adjusted to 30° C. to 150° C., andthe low boiling point components are removed by distillation. Thereaction may be terminated when alcohol is no longer extracted. A knownreactor may be used, and preferred is a stirring vessel in which coolingand heating can be performed. Thus, in the method of producing organicpolytitanoxane of the present invention, organic polytitanoxane can beobtained by sequentially or simultaneously performing the two stepsof: 1) preparing a partially hydrolyzed product by partially hydrolyzingtetraalkoxytitanium and 2) removing the generated low boiling pointcomponent including alcohol from the partially hydrolyzed product andsubjecting the product to polycondensation.

Alternatively, an organic polytitanoxane composition may be obtained bypartially hydrolyzing tetrahalotitanium (TiX₄: X═Cl, Br), removing —HXtherefrom and subjecting the resultant to a polycondensation reaction,or by removing —HX from titanium hydroxide and tetrahalotitanium andsubjecting the resultant to a polycondensation reaction. Also preferredis an organic polytitanoxane composition obtained by sequentially orsimultaneously performing the three steps of: 1) preparing a partiallyhydrolyzed product by partially hydrolyzing tetrahalotitanium, 2)removing a low boiling point component from the partially hydrolyzedproduct and subjecting the product to polycondensation and 3) reactingthe resultant with alcohol, removing HX therefrom and alkoxylating thesame.

It is also possible to dealcoholize titanium hydroxide andtetraalkoxytitanium and subject the resultant to polycondensation.

Another well-known method for producing an organic titanoxanecomposition comprises subjecting tetraalkoxytitanium to heating,deetherification and polycondensation. Preferably used is an organicpolytitanoxane composition obtained after removing 0.1 to 2-fold mole,preferably 0.3 to 1.5-fold mole, more preferably 0.5 to 1.2-fold mole ofether based on titanium atoms contained in tetraalkoxytitanium at adeetherification temperature of 100° C. to 300° C., preferably 150° C.to 250° C. over 1 to 300 hours.

These known organic polytitanoxanes obtained by a polycondensationreaction of at least one raw material selected from tetraalkoxytitanium,tetrahalotitanium (TiX₄: X being selected from Cl and Br) and titaniumhydroxide can be used in the present invention.

The above-described organic polytitanoxane and metal-containing catalystmay be used as is, or after exchange of organic groups before use. Forexample, they may be used after exchange of alkoxy groups by reactingwith a composition containing at least one component selected fromalcohol, an aromatic hydroxy compound and carbonic acid ester. In otherwords, they may be used after mixing or reacting with a startingmaterial, a reactant or a by-product of an transesterification or adisproportionation reaction in the present invention.

When a conventional organic titanate is used, more specifically whendimethyl carbonate is used as a starting material, phenol is used as areactant and phenyl titanate [Ph(OPh)₄] (phenol adduct also usable) isused as organic titanate to produce an aromatic carbonate, specifically,methyl phenyl carbonate, methyl titanate [Ti(OMe)₄] may be generated inthe distillation column in the equilibrium reaction due to alkoxyexchange. Since methyl titanate is hardly soluble in the reactionmixture and is subliming, it may adhere to the wall of the distillationcolumn to cause clogging. Surprisingly, however, it has been found thatthe organic polytitanoxane composition (titanate oligomer, etc.) used inthe present invention hardly causes such poor solubility or adhesion towalls due to sublimation.

Whether a Ti—O—Ti bond is present or not may be simply confirmed byelemental analysis of the catalyst and NMR. When the structure of anorganic group bonded or coordinated to Ti is known, the amount ofbridging oxygen derived from Ti—O—Ti can be determined by subtractingthe amount of oxygen atoms derived from the organic group from theelemental analysis value. The number of bridging oxygen involved inTi—O—Ti bonds and the number of the bonds may be determined from theratio of the amount of Ti atoms to the amount of bridging oxygen. Inaddition, the valence of Ti and the number of oxygen atoms involved inTi—O—Ti may be determined by known X-ray crystallographic analysis(e.g., JP-A-2004-256719), assuming that a Ti—O bond is present when theatomic distance between Ti and O is smaller than the sum (2.87 Å) of theionic radii of Ti atom and oxygen atom.

In addition, such polytitanoxane or copolytitanoxane obtained by a knownmethod may be alkoxy-substituted by reacting with alcohol or an aromatichydroxy compound by a known method (e.g., J. inorg. nucl. Chem., Vol.28, 2410 (1966), J. Indian Chem. Soc., Vol. 38, No. 3, p 147-152(1961)). These catalytic components may be a product of a reaction withan organic compound present in the reaction system, e.g., aliphaticalcohols, aromatic monohydroxy compounds, alkylaryl carbonates, diarylcarbonates or dialkyl carbonates or may be heated prior to the reactionin the form of a raw material or a product, or low boiling pointcomponents may be removed therefrom upon heating. The catalyst may be anadduct or an associated form with alcohol or an aromatic hydroxycompound present in the reaction system.

The structure of polytitanoxane obtained by the above-mentioned methodis shown in the above-described formula (14).

Examples of such titanium compounds include 1) linear polytitanaterepresented by the following formula (29) and cyclic polytitanaterepresented by the following formula (30).

(In the formula (29), R⁷² represents an alkyl group having 1 to 10carbon atoms, an aralkyl, aryl or acyl group, R⁷² may be the same ordifferent from each other or may be bonded with each other, and h is aninteger of 1 to 5).

(In the formula (30), R⁷³ represents an alkyl group having 1 to 10carbon atoms, an aralkyl, aryl or acyl group, R⁷³ may be the same ordifferent from each other or may be bonded with each other, and i is aninteger of 1 to 4, j is an integer of 0 to 4, and i+j=4.)

When R⁷² in the formula (29) and R⁷³ in the formula (30) have a smallnumber of carbon atoms, the catalyst itself may not be in the form ofliquid, or may not be in the form of liquid in the reaction systembecause it has extremely low solubility in the liquid phase of thereaction system. Thus, preferred examples of R⁷² and R⁷³ are an alkylgroup having 3 to 10 carbon atoms such as a propyl group (and isomersthereof), a butyl group (and isomers thereof), a pentyl group (andisomers thereof), a hexyl group (and isomers thereof), a heptyl group(and isomers thereof), an octyl group (and isomers thereof), a nonylgroup (and isomers thereof), a decyl group (and isomers thereof), acyclobutyl group, a cyclopentyl group (and isomers thereof) and acyclohexyl group (and isomers thereof). Those containing an ether bondare also useful, and examples thereof include alkyl groups such as amethoxyethyl group (and isomers thereof), an ethoxyethyl group (andisomers thereof), a methoxypropyl group (and isomers thereof), anethoxypropyl group (and isomers thereof), a methoxybutyl group (andisomers thereof) and an ethoxybutyl group (and isomers thereof).Preferred examples thereof also include aralkyl groups having 7 to 12carbon atoms which may have a substituent, such as a benzyl group and aphenylethyl group. Preferred examples thereof also include aryl groups,e.g. phenyl or alkylphenyl groups such as phenyl, tolyl (and isomersthereof), xylyl (and isomers thereof), trimethylphenyl (and isomersthereof), tetramethylphenyl (and isomers thereof), ethylphenyl (andisomers thereof), propylphenyl (and isomers thereof), butylphenyl (andisomers thereof), diethylphenyl (and isomers thereof), methylethylphenyl(and isomers thereof), pentylphenyl (and isomers thereof), hexylphenyl(and isomers thereof) and cyclohexylphenyl (and isomers thereof);alkoxyphenyl groups such as methoxyphenyl (and isomers thereof),ethoxyphenyl (and isomers thereof) and butoxyphenyl (and isomersthereof); halogenated phenyl groups such as fluorophenyl (and isomersthereof), chlorophenyl (and isomers thereof), bromophenyl (and isomersthereof), chloro(methyl)phenyl (and isomers thereof) and dichlorophenyl(and isomers thereof).

Examples of such compounds include compounds whose structural formula isas described below, e.g., butoxy titanate dimer, phenoxy titanateoligomers such as phenoxy titanate dimer, phenoxy titanate trimer andphenoxy titanate tetramer (and isomers thereof), phenoxy salicyltitanate oligomers such as phenoxy-salicyl-titanate dimer andphenoxy-salicyl-titanate trimer, titanate dimer (derived from phenol andbisphenol A) and titanate trimer (derived from phenol and bisphenol A).Compounds containing 2 to 6 Ti atoms in a molecule are preferred interms of their solubility. Titanate oligomers have molecular weightdistribution, and they may contain a component which does not satisfythe molecular weight of 450 or more defined in the present invention, orcontain a component whose vapor pressure at 230° C. is 10 Pa or higher.Such titanate oligomers may be used as is, but they may be used afterremoving low boiling point components or low molecular weight componentsby distillation.

These catalytic components may be a product of a reaction with anorganic compound present in the reaction system, e.g., aliphaticalcohol, an aromatic monohydroxy compound, alkylaryl carbonate, diarylcarbonate or dialkyl carbonate or may be heated prior to the reaction inthe form of a raw material or a product, or low boiling point componentsmay be removed therefrom upon heating.

Examples of compounds represented by the formula (15) includemonoalkyltin (IV) alkoxide oxide. Among the scientists of the researchfield concerned, it is a common knowledge that no Sn═O double bond isgenerally present and monoalkyltin (IV) alkoxide oxide is usuallypresent in the form of an oligomer of bonded molecules. Examples of suchcompounds include butyltin (IV) butyloxide oxide, butyltin (IV)(2-ethylbutyloxide) oxide, butyltin (IV) (3-methoxypropyloxide) oxide,butyltin (IV) (2-methoxyethoxide) oxide, butyltin (IV)(2-ethoxyethoxide) oxide, butyltin (IV) phenoxide oxide, octyltin (IV)butyloxide oxide, octyltin (IV) (2-ethylbutyloxide) oxide, octyltin (IV)(3-methoxypropyloxide) oxide, octyltin (IV) (2-methoxyethoxide) oxide,octyltin (IV) (2-ethoxyethoxide) oxide and octyltin (IV) phenoxideoxide.

The types of the reaction vessel used in the present invention are notparticular limited, and any conventional reaction vessel such as astirring vessel, a multi-stage stirring vessel, a multi-stagedistillation column or a combination of these may be used. Thesereaction vessels may be used for either a batchwise reaction or acontinuous reaction. In order to efficiently shift the equilibrium ofthe reaction in the direction of the product system, a process using amulti-stage distillation column is preferred, and a continuous processusing a multi-stage distillation column is more preferred. Multi-stagedistillation columns have two or more theoretical distillation stages,and any type may be used as long as it is capable of performingcontinuous distillation.

As such a multi-stage distillation column, any generally usedmulti-stage distillation column may be used, and examples thereofinclude plate type columns using a tray such as a bubble-cap tray, asieve tray, a valve tray or a counterflow tray, and packed type columnspacked with any of various packings such as a Raschig ring, a Lessingring, a Pall ring, a Berl saddle, an Interlox saddle, a Dixon packing, aMcMahon packing, a Heli pack, a Sulzer packing and Mellapak. Further, aplate-packed column combined type having both a plate column section anda packed column section with packings may also be preferably used. Whena continuous process using a multi-stage distillation column is appliedto the production of aromatic carbonates, starting materials andreactants are supplied to a continuous multi-stage distillation columnand these materials are allowed to react with each other in the presenceof a metal-containing catalyst in a liquid phase or in a gas-liquidphase in the distillation column while simultaneously extracting theproduced high boiling point reaction mixture containing aromaticcarbonate or an aromatic carbonate mixture in a liquid form from thebottom of the column, while continuously distilling off the produced lowboiling point reaction mixture containing a by-product in the form ofgas from the upper part of the distillation column by distillation.

The catalyst in the present invention is used in a proportion of usually0.0001 to 30% by weight, preferably 0.001 to 10% by weight, morepreferably 0.01 to 5% by weight based on the total weight of the rawmaterials, although the proportion depends on the kind of the catalystused, the kind and the amount of raw materials and reaction conditionssuch as reaction temperature and reaction pressure. The reaction time(residence time in a continuous process) in the present invention is notparticular limited, and is usually 0.001 to 50 hours, preferably 0.01 to10 hours, more preferably 0.05 to 5 hours.

The reaction is performed at a reaction temperature of usually 50 to350° C., preferably 100 to 280° C. depending on the kind of raw materialcompounds used. The reaction is performed under reduced pressure,atmospheric pressure or increased pressure, usually at 0.1 to 2.0×10⁷ Padepending on the kind of the raw material compounds used and thereaction temperature. In the present invention, it is not alwaysnecessary to use a reaction solvent, but an appropriate inert solventsuch as ether, aliphatic hydrocarbon, aromatic hydrocarbon orhalogenated aromatic hydrocarbon may be used as a reaction solvent inorder to facilitate the reaction procedure.

The present invention has a feature that liquid containing high boilingpoint materials and a metal-containing catalyst is removed from thereaction system and produced aromatic carbonate is transported in theform of gas, and the liquid containing the metal-containing catalyst isrecycled in the system.

In this process, part of the liquid containing a metal-containingcatalyst may be blown down and a fresh catalyst may be added to theliquid. Also, the liquid may be reacted with an active substance toproduce a reaction mixture of a substance derived from a high boilingpoint material and a substance derived from a metal-containing catalyst,and the mixture is separated into a component composed mainly of asubstance derived from a high boiling point material and a componentcomposed mainly of a substance derived from a metal-containing catalyst,and the substance derived from a metal-containing catalyst may berecycled in the system.

The term “reaction system” refers to the space inside the reactor,piping and equipment surrounding the reactor, equipment and piping forthe catalyst recovery system. The “liquid containing a high boilingpoint material and a metal-containing catalyst” in the present inventionrefers to liquid containing a catalyst and a high boiling point materialsupplied to the reactor, a reaction mixture containing a catalyst and ahigh boiling point material present in the reactor, a reaction mixturecontaining a catalyst and a high boiling point material discharged fromthe reactor and a concentrated liquid having increased concentration ofa catalyst and a high boiling point material by evaporation of part ofthe reaction mixture. The catalyst may be completely dissolved in theliquid or present in the form of slurry. In the case of slurry,undissolved portions in the slurry are also included in the “liquidcontaining a high boiling point material and a metal-containingcatalyst”.

The “high boiling point material” in the present invention is an organicsubstance whose boiling point is the same as or higher than that ofaromatic carbonate produced in the present invention. Examples thereofinclude aromatic polyhydroxy compounds and residues thereof, aromaticcarboxyl compounds and residues thereof and xanthones. Another exampleof such high boiling point material is a high molecular weightby-product produced by an additional reaction of the above-describedaromatic polyhydroxy compounds and residues thereof, aromatic carboxylcompounds and residues thereof and xanthones.

The aromatic polyhydroxy compound is represented by the followingformula (31):Ar⁶—(OH)_(q)  (31)(wherein Ar⁶ is an aromatic group having a valence of q, q is an integerof 2 or more, and each —OH group may be bonded to any position of Ar⁶group).

The residue of the aromatic polyhydroxy compound is represented by thefollowing formula (32) and is chemically bonded to at least one memberselected from the group consisting of metal of a metal-containingcatalyst, an alkoxycarbonyl group derived from dialkyl carbonate oralkylaryl carbonate, an aryloxycarbonyl group derived from alkylarylcarbonate or diaryl carbonate and a carbonyl group derived from dialkylcarbonate, alkylaryl carbonate or diaryl carbonate—(O)_(v)—Ar⁶—(OH)_(q-v)  (32)(wherein Ar⁶ and q are as defined above, v is an integer of 1 to m, andan —OH group and an —O— group may be bonded to any position of thearomatic ring of Ar⁶ group).

Examples of Ar⁶ in the formulas (23) and (24) include aromatic groupsrepresented by the following formulas (33), (34), (35), (36) and (37):

(wherein Y¹ is a single bond, a divalent alkylene group having 1 to 30carbon atoms or a divalent group selected from —O—, —CO—, —S—, —SO₂—,—SO— and —COO—);

(wherein Y¹ is as defined above and each Y¹ may be the same ordifferent); and

(wherein Z represents a trivalent group such as a trivalent alkanetriylgroup having 1 to 30 carbon atoms and a trivalent aromatic group; atleast one hydrogen atom on an aromatic ring may be substituted byanother substituent such as a halogen atom, an alkoxy group having 1 to30 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyanogroup, an ester group, an amide group or a nitro group).

Specific examples of aromatic polyhydroxy compounds described aboveinclude hydroquinone, resorcin, catechol, trihydroxybenzene (and isomersthereof), bis-(hydroxyphenyl)-propane (and isomers thereof),bis-(hydroxyphenyl)-methane (and isomers thereof),bis-(hydroxyphenyl)-ether (and isomers thereof),bis-(hydroxyphenyl)-ketone (and isomers thereof),bis-(hydroxyphenyl)-sulfone (and isomers thereof),bis-(hydroxyphenyl)-sulfide (and isomers thereof), dihydroxydiphenyl(and isomers thereof), bis-(dihydroxyphenyl)methane (and isomersthereof), 2-(hydroxyphenyl)-hydroxypropyl-phenol,dihydroxy-(hydroxyphenyldiphenyl) (and isomers thereof),tri-(hydroxyphenyl)ethane (and isomers thereof),tri-(hydroxyphenyl)-benzene (and isomers thereof), dihydroxynaphthalene(and isomers thereof) and trihydroxynaphthalene (and isomers thereof).

Of these aromatic polyhydroxy compounds and residues thereof, compoundsthat are often found in the process for producing the aromatic carbonateof the present invention need a careful attention. Examples of aromaticpolyhydroxy compounds often found in the production process include thefollowing (A), (B) and (C).

-   (A) oxidation product of aromatic monohydroxy compound which is a    reactant-   (B) product produced by Fries rearrangement of diaryl carbonate    obtained by the present reaction and oxidation product thereof-   (C) aromatic dihydroxy compound derived from phenol which is a    reactant, represented by the following formula (38) and oxidation    product thereof:

(wherein Y¹ is as defined above).

Examples of oxidation products (A) of an aromatic monohydroxy compoundinclude compounds represented by the following formulas (39) and (40):

Examples of products (B) produced by Fries rearrangement of diarylcarbonate include compounds represented by the following formulas (41),(42) and (43).

Examples of oxidation products of the compound represented by theformula (41) include compounds represented by the formulas (44) and(45). Examples of oxidation products of the compounds represented by theformulas (42) and (43) include compounds represented by the formulas(46) and (47).

Examples of aromatic dihydroxy compounds (C) represented by the formula(38) include compounds represented by the formula (48).

Examples of oxidation products of the compound represented by theformula (48) include compounds represented by the formulas (49) and(50).

(wherein Y¹ is as defined above).

An aromatic polyhydroxy compound of type (A) is present in theproduction process because it is produced by oxidation of an aromaticmonohydroxy compound due to mixing of a trace amount of oxygen to thesystem when producing aromatic carbonate, or because it is incorporatedinto the reaction system as impurities contained in the raw materialaromatic monohydroxy compound. Typical examples of aromatic polyhydroxycompound (A) include dihydroxybenzene (and isomers thereof) anddihydroxydiphenyl (and isomers thereof).

A product produced by Fries rearrangement of diaryl carbonate of type(B) tends to be produced by a side reaction upon producing diarylcarbonate. Examples of polyhydroxy compounds (B) include2,2′-dihydroxybenzophenone, 2,4′-dihydroxybenzophenone and4,4′-dihydroxybenzophenone.

An aromatic dihydroxy compound of type (C) is a compound generally usedas a monomer for producing aromatic polycarbonate. Aromaticpolycarbonate can be produced by an transesterification of such aromaticdihydroxy compound and diaryl carbonate, and in the transesterification,an aromatic monohydroxy compound is produced as a by-product. Thearomatic dihydroxy compound of type (C) is easily mixed to theproduction process when the by-product aromatic monohydroxy compound isto be used as a reactant in the present invention. Typical examples ofsuch polyhydroxy compounds include 2,2-bis-(4-hydroxyphenyl)-propane.

The aromatic polyhydroxy compounds in the present invention also includean aromatic polyhydroxy compound described below, which is generallycoexistent with 2,2-bis-(4-hydroxyphenyl)-propane:

The aromatic carboxyl compound categorized as a high boiling pointmaterial in the present invention is represented by the formula (51):

(wherein Ar⁷ is an aromatic group having a valence of r, r is an integerof 1 or more, s is an integer of 0 to r−1, and each —OH group and—(COOH) group may be bonded to any position of Ar⁷ group).

The residue of the aromatic carboxyl compound is represented by theformula (52) and is chemically bonded to at least one member selectedfrom the group consisting of metal of a metal-containing catalyst, analkoxycarbonyl group derived from dialkyl carbonate or alkylarylcarbonate, an aryloxycarbonyl group derived from alkylaryl carbonate ordiaryl carbonate and a carbonyl group derived from dialkyl carbonate,alkylaryl carbonate or diaryl carbonate.

(wherein Ar⁷, r and s are as defined above, t is an integer of 0 to s, uis an integer of 0 to r−s, and —OH group, —(COOH) group, —O— group and—(COO)— group may be bonded to any position of Ar⁷).

The particular example of such aromatic carboxyl compounds and itsresidues include: aromatic carbonic acids such as benzoic acid,terephthalic acid, isophthalic acid, phthalic acid or the like; aromaticcarbonates, such as methyl benzoate, phenyl benzoate, dimethylterephtharate or the like; hydroxyl aromatic carbonic acids such assalicylic acid, p-hydroxybenzoic acid, m-hydroxybenzoic acid,dihydroxybenzoic acid (isomers thereof), carboxy diphenol (isomersthereof), 2-(4-hydroxyphenyl)-2-(3′-carboxy-4′-hydroxyphenyl)propane orthe like; aryloxycarbonyl-(hydroxyl)-arenes such as phenyl salicylate,phenyl p-hydroxybenzoate, tolyl salicylate, tolyl p-hydroxybenzoate,phenyl dihydroxybenzoate (isomers thereof), tolyl dihydroxybenzoate(isomers thereof), phenoxycarbonyl diphenol (isomers thereof),2-(4-hydroxyphenyl)-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane orthe like; alkoxycarbonyl-(hydroxyl)-arenes such as methyl salicylate,methyl p-hydroxybenzoate, ethyl salicylate, ethyl p-hydroxybenzoate,methyl dihydroxybenzoate (isomers thereof), methoxycarbonyl diphenol(isomers thereof),2-(4-hydroxyphenyl)-2-(3′-methoxycarbonyl-4′-hydroxyphenyl)propane orthe like; aryloxycarbonyl-(alkoxy)-arenes such as phenyl methoxybenzoate(isomers thereof), tolyl methoxybenzoate (isomers thereof), phenylethoxybenzoate (isomers thereof), tolyl ethoxybenzoate (isomersthereof), phenyl hydroxyl-methoxybenzoate (isomers thereof),hydroxyl-methoxy-(phenoxycarbonyl)-diphenyl (isomers thereof),2-(4-methoxyphenyl)-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-(3′-phenoxycarbonyl-4′-methoxyphenyl)propane orthe like; aryloxycarbonyl-(aryloxy)-arenes such as phenylphenoxybenzoate (isomers thereof), tolyl phenoxybenzoate (isomersthereof), tolyl tolyloxybenzoate (isomers thereof), phenylhydroxyl-phenoxy-benzoate (isomers thereof),hydroxyl-phenoxy-(phenoxycarbonyl)-diphenyl (isomers thereof),2-(4-phenoxyphenyl)-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-(3′-phenoxycarbonyl-4′-phenoxyphenyl)propane orthe like; alkoxycarbonyl-(alkoxy)-arenes such as methyl methoxybenzoate(isomers thereof), ethyl methoxybenzoate (isomers thereof), methylethoxybenzoate (isomers thereof), ethyl ethoxybenzoate (isomersthereof), methyl hydroxyl-methoxybenzoate (isomers thereof),hydroxyl-methoxy-(methoxycarbonyl)-diphenyl (isomers thereof),2-(4-methoxyphenyl)-2-(3′-methoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-(3′-methoxycarbonyl-4′-methoxyphenyl)propane orthe like; alkoxycarbonyl-(aryloxy)-arenes such as methyl phenoxybenzoate(isomers thereof), ethyl phenoxybenzoate (isomers thereof), methyltolyloxybenzoate (isomers thereof), ethyl tolyloxybenzoate (isomersthereof), phenyl hydroxyl-methoxy-benzoate (isomers thereof),hydroxyl-methoxy-(phenoxycarbonyl)-diphenyl (isomers thereof),2-(4-methoxyphenyl)-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-(3-phenoxycarbonyl-4′-methoxyphenyl)propane or thelike; aryloxycarbonyl-(aryloxycarbonyloxy)-arenes such as phenylphenoxycarbonyloxybenzoate (isomers thereof), tolylphenoxycarbonyloxybenzoate (isomers thereof), tolyltolyloxycarbonyloxybenzoate (isomers thereof), phenylhydroxyl-phenoxycarbonyloxy-benzoate (isomers thereof),hydroxyl-phenoxycarbonyloxy-(phenoxycarbonyl)-diphenyl (isomersthereof),2-[4-(phenoxycarbonyloxy)phenyl-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-[3′-phenoxycarbonyl-4′-(phenoxycarbonyloxy)phenyl]propaneor the like; aryloxycarbonyl-(alkoxycarbonyloxy)-arenes such as phenylmethoxycarbonyloxybenzoate (isomers thereof), tolylmethoxycarbonyloxybenzoate (isomers thereof), phenylethoxycarbonyloxybenzoate (isomers thereof), tolylethoxycarbonyloxybenzoate (isomers thereof), phenylhydroxyl-methoxycarbonyloxy-benzoate (isomers thereof),hydroxyl-methoxycarbonyloxy-(phenoxycarbonyl)-diphenyl (isomersthereof),2-[4-(methoxycarbonyloxy)phenyl]-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-[3′-phenoxycarbonyl-4′-(methoxyccarbonyloxy)phenyl]propaneor the like; alkoxycarbonyl-(aryloxycarbonyloxy)-arenes such as methylphenoxycarbonyloxybenzoate (isomers thereof), ethylphenoxycarbonyloxybenzoate (isomers thereof), methyltolyloxycarbonyloxybenzoate (isomers thereof), ethyltolyloxycarbonyloxybenzoate (isomers thereof), methylhydroxyl-phenoxylcarbonyloxybenzoate (isomers thereof),hydroxyl-phenoxycarbonyloxy-(methoxycarbonyl)-diphenyl (isomersthereof),2-[4-(phenoxycarbonyloxy)phenyl]-2-(3′-methoxycarbonyl-4′-hydroxyphenyl)propane,2-(4-hydrorxyphenyl)-2-[3′-methoxycarbonyl-4′(phenoxycarbonyloxy)phenyl]propaneor the like; alkoxycarbonyl-(alkoxycarbonyloxy)-arenes such as methylmethoxycarbonyloxybenzoate (isomers thereof), ethylmethoxycarbonyloxybenzoate (isomers thereof), methylethoxycarbonyloxybenzoate (isomers thereof), ethylethoxycarbonyloxybenzoate (isomers thereof), methylhydroxyl-methoxycarbonyloxy-benzoate (isomers thereof),hydroxyl-methoxycarbonyloxy-(methoxycarbonyl)-diphenyl (isomersthereof),2-[4-(methoxycarbonyloxy)phenyl]-2-(3′-methoxyarbonyl-4′-hydroxyphenyl)propane,2-(4-hydroxyphenyl)-2-[3′-methoxycarbonyl-4′-(methoxycarbonyloxy)phenyl]propaneor the like.

Among these aromatic carboxyl compounds and the residues thereof, thespecial attentions should be paid those tend to exist in the productionprocess of aromatic carbonates of the present invention. Aromaticcarboxyl compounds that tend to exist may include (D) and (E) describedbelow.

(D) includes products of Fries rearrangement of aromatic carbonateswhich are obtained by the transesterification of the present invention,and hydrolysis products thereof. (E) includes products of Friesrearrangement of the transesterification products of the aromaticpolyvalent hydroxyl compounds and hydrolysis products thereof.

As described earlier, in the production method of aromatic carbonates ofthe present invention, the reactions to obtain butyl phenyl carbonateand diphenyl carbonate from dibutylcarbonate and phenol are particularlyimportant, and therefore, aromatic carboxyl compounds and residuesthereof of (D) and (E) described above are shown below as examples.

Example of (D) may include: salicylic acid; p-hydroxybenzoic acid;phenyl salicylate; phenyl p-hydroxybenzoate, butyl salicylate; butylp-hydroxybenzoate; phenyl butoxybenzoate (isomers thereof); phenylphenoxybenzoate (isomers thereof); phenyl phenoxycarbonyloxybenzoate(isomers thereof); butyl phenoxycarbonyloxybenzoate (isomers thereof);butyl butoxycarbonyloxybenzoate (isomers thereof) or the like.

Example of (E) may include: dihydroxybenzoic acid (isomers thereof);phenyl dihydroxybenzoate (isomers thereof); phenoxycarbonyl diphenol(isomers thereof);2-(4-hydroxyphenyl)-2-(3′-phenoxycarbonyl-4′-hydroxyphenyl)propane orthe like.

Xanthones that are included in the high boiling point materials of thepresent invention include xanthone and the xanthone having at least onesubstituent on the aromatic ring selected from following varioussubstituent group consisting of: alkyl groups such as a methyl group,ethyl group, propyl group, isopropyl group, butyl group, and isobutylgroup; hydroxyl group; alkoxy groups such as a methoxy group, ethoxygroup, propoxy group, isopropoxy group, and butoxy group; aryloxy groupssuch as a phenoxy group, tolyloxy group; alkoxycarbonyloxy groups suchas a methoxycarbonyloxy group, ethoxycarbonyloxy group,propoxycarbonyloxy group, and buthoxycarbonyloxy group;aryloxycarbonyloxy groups such as a phenoxycarbonyloxy group,tolyroxycarbonyloxy group; a carboxyl group; alkoxycarbonyl groups suchas a methoxycarbonyl group and ethoxycarbonyl group; aryloxycarbonylgroups such as a phenoxycarbonyl group and tolyloxycarbonyl group; andarylcarbonyloxy groups such as a benzoiloxy group and tolylcarbonyloxygroup.

An active substance in the present invention is a substance that reactswith a high boiling point material and/or a metal-containing catalyst,and any substance may be used as long as a separable reaction mixture isproduced as the result of the reaction. For example, the activesubstance includes an oxidizing agent, a reducing agent, a precipitatingagent, an adsorption agent, a reactive solvent or the like. Inparticular, the oxidizing agent, precipitating agent, reactive solventor the like are preferably used. These active substances may be usedsingly, or in combination of 2 kinds and further simultaneously orsequentially.

The product derived from the high boiling point substance in the presentinvention is the reaction products and/or un-reacted high boiling pointsubstances that results from the reaction between the high boiling pointsubstance and the active substance.

Also the product derived from the metal-containing catalyst is thereaction products and/or un-reacted metal-containing catalyst thatresults from the reaction between the metal-containing catalyst and theactive substance.

The separation of the reaction mixture containing the product derivedfrom the high boiling point substance and the product derived from themetal-containing catalyst may be carried out by any separation method aslong as the method is able to separate this reaction mixture into twocomponents, one that mainly contains the product derived from the highboiling point substance and the other that mainly contains the productderived from the metal-containing catalyst. For example,gas-condensation phase separation methods such as gas-liquid separation,gas-solid separation, gas-solid liquid phase separation or the likemethod; solid-liquid separation methods such as sedimentation,centrifugation, filtration or the like method; distillation method;extraction method; adsorption method; or the like may be used, andpreferably, separation methods such as sedimentation, distillation, andadsorption are used. Further, these separation methods may be usedsingly, or in combination of the two or more methods simultaneously orsequentially.

The combination of this active substance and the separation method isnot limited in particular, but the preferred methods for carrying outthe present invention includes as follows.

(I) The gas-condensation phase separation method, wherein the activesubstance is an oxidizing agent, the reaction is an oxidizing reaction,the product derived from the high boiling point material are low boilingpoint oxidized products, and the product derived from themetal-containing catalyst is metallic oxide.

(II) The solid-liquid separation method, wherein the active substance isa precipitating agent, the reaction is the precipitating reaction, andthe product derived from the metal-containing catalyst is the metalcontaining solid substance which presents in the reaction mixture.

(III) The distillation separation method, wherein the active substanceis a reactive solvent, the reaction is the solvolysis, and the productderived from high boiling point material is one of the solvolysis withlow boiling point.

On using the aforementioned method of (I), the oxidizing agent to beused is the one that oxidizes high boiling point material producing lowboiling point oxidation products as the derivatives of the high boilingpoint material, and that oxidizes the metal-containing catalystproducing metallic oxide as the product derived from themetal-containing catalyst. Examples of those oxidizing agents include:air, molecular oxygen, ozone, hydrogen peroxide, silver oxide; organicperoxides such as peracetic acid, perbenzoic acid, benzoyl peroxide,tert-butylhydroperoxide, cumyl hydroperoxide or the like; oxo-acids suchas nitrous acid, nitric acid, chloric acid, and hypochlorous acid andsalts thereof or the like. Air, molecular oxygen, ozone, hydrogenperoxide, nitrous acid, and nitric acid are preferably used, and morepreferably air and molecular oxygen are used.

The reaction between the liquid and an oxidizing agent is carried out ina phase selected from the group consists of liquid phase, gas-liquidmixed phase and gas-liquid solid mixed phase, although the reactiondepends on the kind of the oxidizing agent and the reaction conditions.The reaction temperature, although it may be varied depending on thekind of oxidizing agent used, is normally −30-2000° C., preferably0-1200° C. and more preferably 0-900° C. The reaction time, although itmay be varied depending on the kind of the oxidizing agent and thereaction time, is normally 0.001-100 hours, preferably 0.1-20 hours. Thereaction pressure is normally carried out under 10-10⁷ Pa, andpreferably 10²-3×10⁶ Pa. This reaction may be carried out in a batchreaction or in continuous reaction.

In the method of the aforementioned (I), the separation of the reactionmixture is carried out by gas-condensation phase separation. Thecondensation phase means liquid phase, solid phase or mixed phase ofsolid and liquid. If the reaction mixture of the aforementionedoxidizing reaction is in liquid phase at the end of the oxidizingreaction, gas liquid mixed phase or gas liquid solid mixed phase, thecondensed phase components consisting of mainly metal oxide may beobtained: by carrying out phase separation of the reaction mixture intothe gas phase components consisting of mainly low boiling point productsof oxidization and the condensation phase containing metal oxides; andby distilling or evaporating low boiling point oxidation products fromthe obtained condensation phase components.

If the metal-containing catalyst in the liquid is oxidized to metaloxide forming solid phase during the progression of the aforementionedoxidation reaction, the solid liquid mixture may be obtained while thereaction is in progress.

Further, the oxidation reaction mixture may be converted into solidphase only by evaporating the low boiling point oxidation product, whichis produced by the oxidation of the high boiling point material,together with the volatile components in the liquid. This is thepreferred method because, simultaneously with the oxidizing reaction,the solid phase which mainly consists of metal oxide is separated fromthe gas phase containing the low boiling point oxidation product.

The low boiling point oxidation product is a compound that is producedby the oxidation of a high boiling point material by the oxidizingagent, having a lower boiling point than that of the high boiling pointmaterial. The examples of the low boiling point oxidation productinclude carbon dioxide, water, carbon monoxide, organic compoundscontaining oxygen, unsaturated organic compounds, the high boiling pointmaterials with reduced carbons or the like, although they may be varieddepending on the kind of the oxidizing agent and high boiling pointmaterial used.

The metal oxide is the oxide of the metal in the metal-containingcatalyst, and includes TiO, Ti₂O₃, TiO₂ or the like. When ametal-containing catalyst having a plurality of metals is used, amixture of the corresponding metal oxides and/or the complex metal oxideis obtained.

In case the method of aforementioned (II) is used, this metal containingsubstance may be any metal containing substance as long as it exists asthe solid in this reaction mixture and contains this metal. For example,it includes: a metal hydroxide; a metal chalcogenide such as metaloxide, a metal sulfide or the like; an inorganic acid salt such as metalcarbonate, metal sulfate or the like; metal organic acid salt; metalcomplex; metal double salt or the like. Metal carbonates, metalhydroxides, metal oxides, metal sulfides and metal sulfates arepreferable because their solubility in this reaction mixture is low. Thereactive substance, starting material or the like may coordinate withthese metal-containing substances.

Any precipitating agent may be used that reacts with themetal-containing catalyst producing the metal containing substancedescribed above. For example, to precipitate these metal hydroxides,inorganic hydroxides such as alkali metal hydroxides, alkali earth metalhydroxide or the like, and water are used. In order to precipitate thesemetal oxides, inorganic oxides such as alkali metal oxides, alkali earthmetal oxides or the like, and oxidizers such as hydrogen peroxide or thelike are used. In order to precipitate these metal sulfides, inorganicsulfides such as alkali metal sulfide, alkali earth sulfide or the like,and hydrogen sulfide are used. In order to precipitate these metalcarbonate, inorganic carbonate salts such as alkali metal carbonates,alkali earth metal carbonates or the like, and carbonic acid, carbondioxide and water are used. In order to precipitate these metal sulfate,inorganic sulfate salts such as alkali metal sulfate, alkali earth metalsalt or the like, sulfuric acid, sulfur trioxide and water are used.

The reaction between the metal-containing catalyst and the precipitatingagent, although it may be varied depending on the kinds of the catalystand the precipitating agent, and the reaction condition used, isnormally carried out in the one phase condition selected from the groupconsisting of liquid phase, gas liquid mixed phase, gas liquid solidmixed phase and solid liquid mixed phase. The reaction temperature,although it may be varied depending on the kind of the precipitatingagent used, is normally −70-600° C., preferably −30-400° C., morepreferably −10-250° C.

The reaction time, although it may be varied depending on the kind ofthe precipitating agent and the reaction temperature, is normally0.001-100 hour, preferably 0.1-20 hours. The reaction is usually carriedout under the pressure of 10-10⁷ Pa. This reaction may be carried out asthe batch or continuous reaction.

In the precipitating reaction, it is the preferable method to add asubstance forming crystal nuclei. Further, although the metal containingsubstance exists as solid on separating this reaction mixture, it doesnot necessarily need to exist as solid while the precipitating reactionis proceeding, and it may be solidified through the operations such ascooling or the like after this reaction. In the case of theaforementioned (II), the separation of the reaction mixture is thesolid-liquid separation, and the mixture is separated to a solid phasemainly consisting of the metal containing substance and a liquid phasemainly consisting of the product derived from the high boiling pointmaterial. For this solid liquid separation, normally sedimentation,centrifugation, filtration or the like separation method are used.

Further in carrying out the method of (II), the high boiling pointmaterial containing in the liquid may react or may not react in theprecipitating reaction.

In case the method of the aforementioned (III) is used, the reactivesolvent to be used may be any reactive solvent as long as it reacts withthe high boiling point material and produces compounds with the boilingpoint lower than that of the high boiling point material. For example,water; lower alcohols such as methanol, ethanol, propanol (isomersthereof), butanol (isomers thereof), or the like; lower carboxylic acidssuch as formic acid, acetic acid, propionic acid or the like; carbonatessuch as dimethyl carbonate, diethyl carbonate, dibutyl carbonate or thelike may be used. Water, methanol, ethanol, acetic acid, methyl acetate,ethyl acetate, dimethyl carbonate, diethyl carbonate, dibutyl carbonateor the like are preferably used and more preferably, water is used.

The solvolysis in the present invention means the reaction between thereactive solvent and the high boiling point material, and the solvolysisproducts may undergo further reactions such as the decarboxylationreaction that is different from the solvolysis reaction. This lowboiling point product of the solvolysis may be a product with a lowerboiling point than the high boiling point material and its variety orstructure may be varied depending upon the reactive solvent and the kindof the high boiling point material. The solvolysis products with lowboiling point are explained particularly in following (i)-(iii), whenthe high boiling point material is phenyl salicylate that is one ofaromatic carboxyl compounds.

(i) In the case where the reactive solvent is water: phenol andsalicylic acid are produced by hydrolysis and this salicylic acidfurther undergoes decarboxylation reaction producing phenol and carbondioxide.

(ii) In the case where the reactive solvent is alcohol: alkyl salicylateand phenol are produced by alcoholysis.

(iii) In the case where the reactive solvent is carboxylic acid:salicylic acid and phenyl carboxylate ester are produced by thetransesterification and this salicylic acid further undergoesdecarboxylation reaction converted into phenol and carbon dioxide.

Above explanation is based on the example of phenyl salicylate that isrelatively simple structured aromatic carboxylic compound but similarreactions involving more complexed aromatic carboxylic compounds mayalso generate corresponding solvolysis products such as aromaticmonohydroxy compound, ester of lower carboxylic acid and aromatic monohydroxyl compound, ester of aromatic carboxyl compound and a loweralcohol, carbon dioxide or the like. In particular, aromatic monohydroxycompounds are preferable as solvolysis products because they are thereactive substances of the present invention and can be reused.

Since the liquid contains the metal-containing catalyst which normallyfunctions as a catalyst for the solvolysis reaction, it is not necessaryto use a catalyst for the solvolysis reaction in particular. However,the catalyst may be used for the purpose of improving the rate ofreaction or the like.

The reaction between the high boiling point material and the reactivesolvent is normally carried out, although it may be varied depending onthe reaction condition, in one phase condition either liquid phase orsolid liquid mixture phase.

The reaction temperature, although it may be varied depending on thekind of the reactive solvent used, is normally −30 to 400° C.,preferably −10 to 300° C., more preferably −0 to 250° C.

The reaction time, although it may be varied depending on the kind ofthe reactive solvent and the reaction temperature, normally 0.001-100hour, preferably 0.1-20 hours. The reaction is usually carried out underthe pressure of 10-10⁷ Pa. This reaction may be carried out as the batchor continuous reaction.

The metal-containing catalyst may or may not catalyze the solvolysisreaction. In case of reacting water or alcohols as the reactive solventto the liquid containing an aromatic carboxylic compound as the highboiling point material, carbon dioxide is generated as one of thederivations from the high boiling point material due to thedecarboxylation. Thus this carbon dioxide acts as the precipitatingagent and reacts with the metal-containing catalyst, and metalcontaining substances such as metal carbonate or the like may beobtained in soluble and/or solidified states.

In the method of the aforementioned (III), the reaction mixture isseparated by distillation, and the low boiling points solvolysisproducts that are the products derived from the high boiling pointmaterial are mainly obtained as distillates. The metal-containingcatalyst remains in the residual liquid in the distillation still. Thisdistillation separation is carried out at the temperature normally10-300° C., preferably 50-250° C., represented as the temperature of theliquid in the distillation still. The reaction is usually carried outunder the pressure of 0.1-1.0×10⁶ Pa, preferably 1.0-1.0×10⁵ Pa. Thedistillation may be carried out batch-wise or continuously.

When the products derived from the metal-containing catalyst, which areobtained by separating the reaction mixture of the liquid from theactive substance, are to be recycled in the system, the compositioncontaining the products derived from the metal-containing catalyst,which are obtained by separation of the reaction mixture, in liquid,solid or liquid solid mixed phase may be recycled into the system asthey are, or if this composition contains other components than theproducts derived from the metal-containing catalyst, a part or the wholecomponents may be separated and then recycled in the system. Further,the reaction solution or slurry, which is obtained by reacting theproducts derived from the metal-containing catalyst to the startingmaterial or to the reactive substance, may be recycled. This method isthe preferred method when the products derived from the metal-containingcatalyst are in a solid or a solid liquid mixed phase.

Concerning the high boiling point liquid materials to be removed fromthe system, those concentrations which may be varied depending on thekind of materials, are not preferred to be kept extremely low becausethe volume of the liquid, which is subjected to the removal, becomes toolarge. Also, if the concentration of the high boiling point material istoo high, handling becomes difficult due to the increase of the boilingpoint and the viscosity. Therefore, the concentration of the highboiling point material in the liquid, which is subjected to the removal,is normally 0.01-99% by weight, preferably 0.1-95% by weight and morepreferably 1-90% by weight.

Further, when the high boiling point material is an aromatic polyvalenthydroxyl compound, the weight ratio of aromatic polyvalent hydroxylcompound to the metal of the catalyst in the liquid is normally kept at2 or below to prevent deposition and attachment of the catalyst in thereactor and the lines.

By using the metal-containing catalyst of the present invention, factorsthat rendered the production unstable in the past such as clogging ofthe distillation column, deposition of the catalyst component to thewall are surprisingly improved.

Further, the preferred example of the present invention includes theusage of diaryl carbonate, purified by the method of the presentinvention, in aromatic polycarbonate production by thetransesterification method. Polycarbonate which is produced by thetransesterification method, depending on the polymerization method,tends to show red coloring due to the metal content in the catalyst fordiphenyl carbonate which is used as the material, especially when the Ticontent is greater than 1 ppm. However, the aromatic carbonate,particularly important diphenyl carbonate, which is produced by themethod of the present invention contains Ti at 1 ppm or below.Polycarbonate is easily produced by the transesterificationpolymerization with bisphenol A. Thus polycarbonate produce in thepresent invention is high quality because it contains less Ti whichcauses coloring of polycarbonate.

Further, in producing aromatic polycarbonate by the transesterificationmethod, the polymerization at high rate may be achieved using the diarylcarbonate produced by the method of the present invention. Stillfurther, aromatic polycarbonate produced by the transesterificationmethod, which is obtained using aromatic dihydroxy compound and diarylcarbonate produced by the method of the present invention, has nocoloring and is high quality.

EFFECT OF THE INVENTION

According to the present invention, high purity diaryl carbonate that iseasily separated from a catalyst is produced, wherein a startingmaterial selected from the group consisting of a dialkyl carbonate, analkylaryl carbonate and a mixture thereof and a reactive substanceselected from the group consisting of an aromatic monohydroxy compound,an alkylaryl carbonate and a mixture thereof are reacted in the presenceof a metal-containing catalyst to produce aromatic carbonates whileby-products alcohols and/or dialkyl carbonates are distilled out of thesystem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow chart related to the production of aromaticcarbonate in the present invention; and

FIG. 2 is a process flow chart related to the purification of diarylcarbonate in the present invention.

FIG. 3 is a process flow chart related to the structure of aromaticcarbonic acid ester.

FIG. 4 is a process flow chart related to the structure of aromaticcarbonic acid ester.

DESCRIPTION OF SYMBOLS

-   1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 54, 57,    58, 60: line-   50, 56: inlet line-   2, 14, 26, 38, 51: preheater-   3, 15, 27, 39, 49: continuous multi-stage distillation column-   5, 17, 29, 41: cooler-   55: condenser-   6, 18, 30, 42: gas liquid separator-   11, 23, 35, 47, 59: reboiler-   8, 12, 20, 24, 33, 36, 44, 48: storage tank-   9, 21, 32, 45: pressure control valve-   52: top of the column-   53: bottom of the column

BEST MODE FOR CARRYING OUT THE INVENTION

Next, the present invention will be explained in particular by theexamples, but the present invention is not limited by these examples.Further, the measurements for the concentration of the catalyst and theconcentration of the metal derived from the metal-containing catalyst inaromatic carbonate were carried out using an ICP/AES (InductivelyCoupled Plasma/Atomic Emission Spectroscopy: Detection limit of 0.1ppm). The concentrations of the organic components in the liquid weremeasured by Gas Chromatography.

-   (1) Conditions for Gas Chromatographic Analysis.

Column: DB-1 (J & W Scientific)

Liquid phase: 100% dimethylpolysiloxane

Length: 30 m

Internal diameter: 0.25 mm

Film thickness: 1 μm

Column temperature: 50° C. (increased by 10° C./min) 300° C.

Injection temperature: 300° C.

Detector temperature: 300° C.

Detection method: FID

-   (2) Quantitative Analysis

The analysis sample solutions are quantitatively analyzed based on thestandard curves prepared by carrying out the analyses on the calibrationsamples of each standard substance.

-   (3) Confirmation of Ti—O—Ti Bond.

The presence of Ti—O—Ti bond is estimated by identifying Ti substituent(or ligand) from the result of ¹H-NMR, and subtracting the oxygen valuederived from this substituent (or ligand) from the result of the elementanalysis (C, H, O, Ti) and by assuming this oxygen value as the crosslinkage oxygen derived from Ti—O—Ti.

-   (4) Conditions for NMR analysis

Device: JNM-A400 FT-NMR system made by JEOL Ltd.

(Preparation of Samples for ¹H-NMR, ¹³C-NMR Analysis)

The metal-containing catalyst was weighed in the range of 0.1 g-1 g andmixed homogeneously with deuterated chloroform (Aldrich Co. 99.8%) orcarbon tetrachloride that weighed in the range of 0.05 g-0.7 g toprepare samples for the NMR analysis. TMS (tetramethyl silane) was usedas the internal standard.

EXAMPLES

The present invention will be described based on the examples.

Example 1

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as the catalyst, phenyltitanate dimer.2PhOH adduct [(PhO)₃—Ti—O—Ti—(OPh)₃.2PhOH] (result ofelement analysis: C=67.2, H=4.93, O=16.77, Ti=11.1; result of ¹H-NMRanalysis: PhOH and PhO groups exist at the ratio of 2:6. In onemolecule, two Ti atoms and one oxygen atom that is not derived from PhOHand PhO groups exist, that is, one Ti—O—Ti bond exists; molecular weightwithout the adduct PhOH: 670; vapor pressure: 1 Pa or below at 230° C.)(the mixed solution in which that the ratio by weight of dibutylcarbonate to phenol was adjusted to about 65/35, and Ti as atoms wasadjusted to about 10,000 ppm of the whole liquid) from the middle stageof a continuous multi-stage distillation column 3, which was composed ofa condensation part, which was 2 inch in the internal diameter, 0.5 m inthe column length and filled with 10 stages of sieve trays, and arecovery part which was 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ). The condensationpart was disposed in the lower part of the stage where the mixture wassupplied continuously, and the recovery part was disposed in the upperpart. The heat required for the reaction and distillation was suppliedby circulating the liquid in the lower part of the column through a line10 and a reboiler 11, and the temperature at the bottom of themulti-stage distillation column was controlled to be about 230° C. Thereaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 3 through a line 10 to astorage tank 12 at 90 g/Hr. The catalyst was dissolved in the reactionliquid.

After the low boiling point liquid mixture containing 1-butanol as aby-product was removed from the top of the column through a line 4, andthen it was liquefied by a cooler 5, and a part of it was removedcontinuously to a storage tank 8 at 19 g/Hr and the rest was refluxed tothe distillation column (reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of about 23% byweight of phenol, about 56% by weight dibutyl carbonate, about 12% byweight of butyl phenyl carbonate, about 0.2% by weight of diphenylcarbonate, about 0.3% by weight of 1-butanol and the catalyst. Theliquid removed to the storage tank 8 was composed of about 99% by weightof 1-butanol, about 0.5% by weight of phenol, and about 0.2% by weightof dibutyl carbonate.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part.

The reaction was carried out by supplying continuously through a line 13the reaction liquid, which was removed from the bottom of the continuousmulti-stage distillation column 3 through the line 10 to the storagetank 12, to the continuous multi-stage distillation column 15 at 100g/Hr after preheating with a preheater 14. The heat required for thereaction and distillation was supplied by circulating the liquid in thelower part of the column through a line 22 and a reboiler 24, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 220° C.

The reaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 15 through the line 22 to astorage tank 24 at 17 g/Hr. After the low boiling point liquid mixturecontaining dibutylcarbonate as a by-product was removed from the top ofthe column through a line 16, and then it was liquefied by a cooler 17,and a part of it was removed continuously to a storage tank 20 at 83g/Hr and the rest was refluxed to the distillation column (refluxratio=4).

The liquid removed to the storage tank 24 was composed of about 5% byweight of dibutyl carbonate, about 74% by weight of butyl phenylcarbonate, about 10% by weight of diphenyl carbonate, and the catalyst.The liquid removed to the storage tank 20 was composed of about 0.3% byweight of 1-butanol, about 18% by weight of phenol, and about 81% byweight of dibutyl carbonate. No deposit or the like were found in thedistillation column on inspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 192 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 34and a reboiler 35, and the temperature at the bottom of the multi-stagedistillation column is controlled to be about 210° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 27 through the line 34 to the storage tank 36 atabout 90 g/Hr. After removing from the top of the column through theline 28, the distillate was liquefied by a cooler 29 and was removedcontinuously to a storage tank 33 at about 102 g/Hr. The liquid removedto the storage tank 33 is composed of dibutyl carbonate: about 0.6% byweight, butyl phenyl carbonate: about 73% by weight, diphenyl carbonate:about 26% by weight.

The distillation separation was carried out by continuously feeding theliquid, which was continuously removed to the storage tank 33, through aline 37 passing a preheater 38 at about 101 g/Hr to the middle stage ofa continuous multi-stage distillation column 39, which was a columnfilled with Dixon packing (6 mmφ) with an internal diameter of 2 inchand a length of 2 m. The heat required for the distillation separationwas supplied by circulating the liquid in the lower part of the columnthrough a line 46 and a reboiler 47, and the temperature at the bottomof the multi-stage distillation column was controlled to be about 200°C. The bottom liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 39 through the line 46 to astorage tank 48 at about 19 g/Hr.

After removing from the top of the column through a line 40, thedistillate was liquefied by a cooler 41 and was removed continuously toa storage tank 44 at about 82 g/Hr. The liquid removed to the storagetank 44 is composed of dibutyl carbonate: about 0.7% by weight, butylphenyl carbonate: about 90% by weight, diphenyl carbonate: about 9% byweight.

White liquid that was solidified at ambient temperature was continuouslyremoved to a storage tank 48 and contained diphenyl carbonate: about100% by weight, and butyl phenyl carbonate was below the detectionlimit. The analysis of the liquid indicated that Ti was below thedetection limit. Inspection of the distillation column revealed notdeposit or the like.

Comparative Example 1

[Production of aromatic carbonate]

Aromatic carbonate was produced in the device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a transport line 1, a mixed solutionconsisting of dibutyl carbonate, phenol, and phenyl titanate [Ti(OPh)₄](this phenyl titanate: adduct with phenol; molecular weight without theadduct phenol: 420; vapor pressure: about 15 Pa at 230° C.) (the mixedsolution in which the ratio by weight of dibutyl carbonate to phenol wasadjusted to about 65/35, and Ti as atoms was adjusted to about 10,000ppm of the whole liquid) from the middle stage of a continuousmulti-stage distillation column 3, which is composed of a condensationpart, which is 2 inch in the internal diameter, 0.5 m in the columnlength and filled with 10 stages of sieve trays, and a recovery partwhich is 2 inch in the internal diameter, 1 m in the column length andfilled with Dixon packing (6 mmφ). The condensation part was disposed inthe lower part of the stage where the mixture was supplied continuously,and the recovery part was disposed in the upper part.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 10and a reboiler 11, and the temperature at the bottom of the multi-stagedistillation column is controlled to be about 230° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 3 through the line 10 to a storage tank12 at 90 g/Hr.

After the low boiling point liquid mixture containing 1-butanol as aby-product was removed from the top of the column through a line 4, andthen it was liquefied by the cooler 5, and a part of it was removedcontinuously to a storage tank 8 at 19 g/Hr and the rest was refluxed tothe distillation column (reflux ratio=1.9). The liquid removed to thestorage tank 12 was composed of: phenol: about 23% by weight, dibutylcarbonate: about 56% by weight, butyl phenyl carbonate: about 12% byweight, diphenyl carbonate: about 0.2% by weight, 1-butanol: about 0.3%by weight. The liquid removed to the storage tank 8 was composed of1-butanol: about 99% by weight, phenol: about 0.5% by weight, anddibutyl carbonate: about 0.2% by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, like thecontinuous multi-stage distillation column 3, is composed of acondensation part, which is 2 inch in the internal diameter, 0.5 m inthe column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part.

The reaction was carried out by supplying continuously through a line 13the reaction liquid, which was removed from the bottom of the continuousmulti-stage distillation column 3 through the line 10 to the storagetank 12, to the continuous multi-stage distillation column 15 at 100g/Hr after preheating with a preheater 14. The heat required for thereaction and distillation was supplied by circulating the liquid in thelower part of the column through a line 22 and a reboiler 24, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 220° C.

The reaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 15 through the line 22 to astorage tank 24 at 17 g/Hr. After the low boiling point liquid mixturecontaining dibutylcarbonate as a by-product was removed from the top ofthe column through a line 16, and then it was liquefied by a cooler 17,and a part of it was removed continuously to a storage tank 20 at 83g/Hr and the rest was refluxed to the distillation column (refluxratio=4).

The liquid removed to the storage tank 24 was composed of dibutylcarbonate: about 5% by weight, butyl phenyl carbonate: about 74% byweight, diphenyl carbonate: about 10% by weight. The liquid removed tothe storage tank 20 was composed of about 1-butanol: 0.3% by weight,phenol: about 18% by weight, and dibutyl carbonate: about 81% by weight.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 34and a reboiler 35, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 210° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 27 through the line 34 to the storage tank 36 atabout 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by the cooler 29 and was removed continuouslyto a storage tank 33 at about 80 g/Hr.

The liquid removed to the storage tank 33 is composed of dibutylcarbonate: about 6% by weight, butyl phenyl carbonate: about 86% byweight, diphenyl carbonate: about 7.5% by weight.

The distillation separation was carried out by continuously feeding theliquid, which was continuously removed to the storage tank 33, through aline 37 passing a preheater 38 at about 100 g/Hr to the middle stage ofa continuous multi-stage distillation column 39, which was a columnfilled with Dixon packing (6 mmφ) with an internal diameter of 2 inchand a length of 2 m. The heat required for the distillation separationwas supplied by circulating the liquid in the lower part of the columnthrough the line 46 and reboiler 47, and the temperature at the bottomof the multi-stage distillation column is controlled to be about 230° C.

The bottom liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 39 through a line 46 to astorage tank 48 at about 8 g/Hr. After removing from the top of thecolumn through the line 40, the distillate was liquefied by a cooler 41and was removed continuously to a storage tank 44 at about 92 g/Hr.

The liquid removed to the storage tank 44 is composed of dibutylcarbonate: about 6% by weight, butyl phenyl carbonate: about 94% byweight.

The liquid removed to a storage tank 48 was solid at ambient temperaturebut had a coloring of red. The analysis of the liquid indicated that Ticontent of about 5 ppm.

Example 2

[Production of aromatic carbonate]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about100 g/Hr, through the preheater 2 and the transport line 1, a mixedsolution consisting of dibutyl carbonate, phenol and, as a catalyst,di(phenyl salicylate) titanate-diphenolate (molecular weight: 660, vaporpressure: 1 Pa or below at 230° C.) (the mixed solution in which theratio by weight of dibutyl carbonate an phenol was adjusted to about65/35, and Ti as atoms was adjusted to about 10,000 ppm of the wholeliquid) from the middle stage of a continuous multi-stage distillationcolumn 3, which is composed of the condensation part, which is 2 inch inthe internal diameter, 0.5 m in the column length and filled with 10stages of sieve trays, and the recovery part which is 2 inch in theinternal diameter, 1 m in the column length and filled with Dixonpacking (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture liquid was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column is controlled to beabout 230° C.

The reaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 3 through the line 10 to astorage tank 12 at 95 g/Hr. The catalyst was dissolved in the reactionliquid.

After the low boiling point liquid mixture containing 1-butanol as aby-product was removed from the top of the column through a line 4, andthen it was liquefied by the cooler 5, and a part of it was removedcontinuously to a storage tank 8 at 5 g/Hr and the rest was refluxed tothe distillation column (reflux ratio=2).

The liquid removed to the storage tank 12 was composed of phenol: about26% by weight, dibutyl carbonate: about 50% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.6% by weight and the catalyst. The liquidremoved to the storage tank 8 was composed of 1-butanol: about 90% byweight, phenol: about 7% by weight, and dibutyl carbonate: about 3% byweight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and therecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part.

The reaction was carried out by supplying continuously through a line 13the reaction liquid, which was removed from the bottom of the continuousmulti-stage distillation column 3 through the line 10 to the storagetank 12, to the continuous multi-stage distillation column 15 at 95 g/Hrafter preheating with a preheater 14. The heat required for the reactionand distillation was supplied by circulating the liquid in the lowerpart of the column through a line 22 and a reboiler 24, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 220° C.

The reaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 15 through the line 22 to astorage tank 24 at about 19 g/Hr. After the low boiling point liquidmixture containing dibutylcarbonate as a by-product was removed from thetop of the column through a line 16, and then it was liquefied by acooler 17, and a part of it was removed continuously to a storage tank20 at 76 g/Hr and the rest was refluxed to the distillation column(reflux ratio=4).

The liquid removed to the storage tank 24 was composed of dibutylcarbonate: about 0.3% by weight, butyl phenyl carbonate: about 38% byweight, diphenyl carbonate: about 14% by weight and also the catalyst.The liquid removed to the storage tank 20 was composed of 1-butanol:about 0.7% by weight, phenol: about 33% by weight, and dibutylcarbonate: about 65% by weight, butyl phenyl carbonate: about 1% byweight. No deposit or the like were found in the distillation column oninspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 192 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 34and a reboiler 35, and the temperature at the bottom of the multi-stagedistillation column is controlled to be about 210° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 27 through the line 34 to the storage tank 36 atabout 90 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 102 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 0.6% by weight, butylphenyl carbonate: about 73% by weight, diphenyl carbonate: about 26% byweight.

The distillation separation was carried out by continuously feeding theliquid, which was continuously removed to the storage tank 33, through aline 37 passing a preheater 38 at about 101 g/Hr to the middle stage ofa continuous multi-stage distillation column 39, which was a columnfilled with Dixon packing (6 mmφ) with an internal diameter of 2 inchand a length of 2 m. The heat required for the distillation separationwas supplied by circulating the liquid in the lower part of the columnthrough a line 46 and a reboiler 47, and the temperature at the bottomof the multi-stage distillation column was controlled to be about 200°C.

The bottom liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 39 through the line 46 to astorage tank 48 at about 19 g/Hr. After removing from the top of thecolumn through a line 40, the distillate was liquefied by a cooler 41and was removed continuously to the storage tank 44 at about 82 g/Hr.

The liquid removed to the storage tank 44 is composed of dibutylcarbonate: about 0.7% by weight, butyl phenyl carbonate: about 90% byweight, diphenyl carbonate: about 9% by weight. White liquid that wassolidified at ambient temperature was continuously removed to a storagetank 48 and contained diphenyl carbonate: about 100% by weight, andbutyl phenyl carbonate was below the detection limit. The analysis ofthe liquid indicated that Ti content was about 0.8 ppm. Inspection ofthe distillation column revealed no deposit or the like.

Example 3

[Production of aromatic carbonate]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through the preheater 2 and the line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, butyltitanate trimer [(BuO)₃—Ti—O—Ti—(OBu)₂—O—Ti—(OBu)₃] (result of elementanalysis: C=50.5, H=9.5, O=21.1, Ti=18.9; since oxygen derived from BuOis 16.8, the number of bridging oxygen is 2, that is, there are twoTi—O—Ti bonds; molecular weight: 760; vapor pressure: 1 Pa or below at230° C.) (the mixed solution in which the ratio by weight of dibutylcarbonate to phenol was adjusted to about 65/35, and Ti as atoms wasadjusted to about 10,000 ppm of the whole liquid, and this catalyst wasdissolved in this mixture) from the middle stage of a continuousmulti-stage distillation column 3, which was composed of a condensationpart, which was 2 inch in the internal diameter, 0.5 m in the columnlength and filled with 10 stages of sieve trays, and a recovery partwhich was 2 inch in the internal diameter, 1 m in the column length andfilled with Dixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture liquid was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C.

The reaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 3 through the line 10 to astorage tank 12 at 90 g/Hr. The catalyst was dissolved in the reactionliquid.

After the low boiling point liquid mixture containing 1-butanol as aby-product was removed from the top of the column through a line 4, andthen it was liquefied by the cooler 5, and a part of it was removedcontinuously to the storage tank 8 at 19 g/Hr and the rest was refluxedto the distillation column (reflux ratio=1.9). The liquid removed to thestorage tank 12 was composed of phenol: about 23% by weight, dibutylcarbonate: about 56% by weight, butyl phenyl carbonate: about 12% byweight, diphenyl carbonate: about 0.2% by weight, 1-butanol: about 0.3%by weight and also the catalyst. The liquid removed to the storage tank8 was composed of 1-butanol: about 99% by weight, phenol: about 0.5% byweight, and dibutyl carbonate: about 0.2% by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part.

The reaction was carried out by continuously supplying through a line 13the reaction liquid, which was removed from the bottom of the continuousmulti-stage distillation column 3 through the line 10 to the storagetank 12, to the continuous multi-stage distillation column 15 at 100g/Hr after preheating with a preheater 14. The heat required for thereaction and distillation was supplied by circulating the liquid in thelower part of the column through a line 22 and a reboiler 24, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 220° C.

The reaction liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 15 through the line 22 to astorage tank 24 at 17 g/Hr. After the low boiling point liquid mixturecontaining dibutylcarbonate as a by-product was removed from the top ofthe column through a line 16, and then it was liquefied by a cooler 17,and a part of it was removed continuously to a storage tank 20 at 83g/Hr and the rest was refluxed to the distillation column (refluxratio=4).

The liquid removed to the storage tank 24 was composed of dibutylcarbonate: about 5% by weight, butyl phenyl carbonate: about 74% byweight, diphenyl carbonate: about 10% by weight and also the catalyst.The liquid removed to the storage tank 20 was composed of 1-butanol:about 0.3% by weight, phenol: about 18% by weight, and dibutylcarbonate: about 81% by weight. No deposit or the like were found in thedistillation column on inspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with the device shownin FIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 192 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 90 g/Hr.After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 102 g/Hr.

The liquid removed to the storage tank 33 is composed of dibutylcarbonate: about 0.6% by weight, butyl phenyl carbonate: about 73% byweight, diphenyl carbonate: about 26% by weight.

The distillation separation was carried out by continuously feeding theliquid, which was continuously removed to the storage tank 33, throughthe line 37 passing a preheater 38 at about 101 g/Hr to the middle stageof the continuous multi-stage distillation column 39, which was a columnfilled with Dixon packing (6 mmφ) with an internal diameter of 2 inchand a length of 2 m. The heat required for the distillation separationwas supplied by circulating the liquid in the lower part of the columnthrough the line 46 and reboiler 47, and the temperature at the bottomof the multi-stage distillation column is controlled to be about 200° C.

The bottom liquid was continuously removed from the bottom of thecontinuous multi-stage distillation column 39 through the line 46 to thestorage tank 48 at about 19 g/Hr.

After removing from the top of the column through the line 40, thedistillate was liquefied by the cooler 41 and was removed continuouslyto the storage tank 44 at about 82 g/Hr. The liquid removed to thestorage tank 44 is composed of dibutyl carbonate: about 0.7% by weight,butyl phenyl carbonate: about 90% by weight, diphenyl carbonate: about9% by weight.

White liquid that was solidified at ambient temperature was continuouslyremoved to the storage tank 48 and contained diphenyl carbonate: about100% by weight, and butyl phenyl carbonate was below the detectionlimit. The analysis of the liquid indicated that Ti content was belowthe detection limit. No deposit or the like were found in thedistillation column on inspection.

Example 4

[Production of aromatic carbonate]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through the preheater 2 and the transport line 1, a mixedsolution consisting of dibutyl carbonate, phenol and, as a catalyst, anorganic polytitanoxan composition (Matsumoto Trading Co. Ltd. OrgaticsTA-22) containing butyl titanate dimer [(BuO)₃—Ti—O—Ti—(OBu)₃](molecular weight: 550; vapor pressure: 1 Pa or below at 230° C.) (themixed solution in which the ratio by weight of dibutyl carbonate andphenol was adjusted to 65/35, and Ti as atoms was adjusted to about10,000 ppm of the whole liquid, and this catalyst was dissolved in thismixture) from the middle stage of the continuous multi-stagedistillation column 3, which was composed of a condensation part, whichwas 2 inch in the internal diameter, 0.5 m in the column length andfilled with 10 stages of sieve trays, and a recovery part which was 2inch in the internal diameter, 1 m in the column length and filled withDixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture liquid was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through the line 10 and reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. After the low boiling pointliquid mixture containing 1-butanol as a by-product was removed from thetop of the column through a line 4, and then it was liquefied by thecooler 5, and a part of it was removed continuously to the storage tank8 at 19 g/Hr and the rest was refluxed to the distillation column(reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and also the catalyst. Theliquid removed to the storage tank 8 was composed of 1-butanol: about99% by weight, phenol: about 0.5% by weight, and dibutyl carbonate:about 0.2% by weight.

After the continuous multi-stage distillation column 3, the reaction wascarried out using the continuous multi-stage distillation column 15. Thecontinuous multi-stage distillation column 15, as in the case of thecontinuous multi-stage distillation column 3, was composed of thecondensation part, which is 2 inch in the internal diameter, 0.5 m inthe column length and filled with 10 stages of sieve trays, and therecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through the line 13 the reaction liquid, whichwas removed from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through the line22 and reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by the cooler 17, and apart of it was removed continuously to a storage tank 20 at 83 g/Hr andthe rest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and also the catalyst. Theliquid removed to the storage tank 20 was composed of 1-butanol: about0.3% by weight, phenol: about 18% by weight, and dibutyl carbonate:about 81% by weight. No deposit or the like were found in thedistillation column on inspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with the device shownin FIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, throughthe line 25 passing a preheater 26 at about 100 g/Hr to about 0.1 mabove the middle stage of the continuous multi-stage distillation column27, which was a column filled with Dixon packing (6 mmφ) with aninternal diameter of 2 inch and a length of 1 m. The heat required forthe distillation separation was supplied by circulating the liquid inthe lower part of the column through the line 34 and reboiler 35, andthe temperature at the bottom of the multi-stage distillation column iscontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by the cooler 29 and was removed continuouslyto a storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed continuously to thestorage tank 33, through the line 37 passing a preheater 38 at about 100g/Hr to the middle stage of the continuous multi-stage distillationcolumn 39, which was a column filled with Dixon packing (6 mmφ) with aninternal diameter of 2 inch and 2 m length.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through the line46 and reboiler 47, and the temperature at the bottom of the multi-stagedistillation column is controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to the storage tank 48 atabout 8 g/Hr. After removing from the top of the column through the line40, the distillate was liquefied by the cooler 41 and was removedcontinuously to the storage tank 44 at about 92 g/Hr. The liquid removedto the storage tank 44 is composed of dibutyl carbonate: about 6% byweight, butyl phenyl carbonate: about 94% by weight. White liquid thatwas solidified at ambient temperature was continuously removed to thestorage tank 48 and contained diphenyl carbonate: about 100% by weight,and butyl phenyl carbonate was below the detection limit. The analysisof the liquid indicated that Ti content was below the detection limit.No deposit or the like were found in the distillation column oninspection.

Example 5

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a transport line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, titaniummethyl phenoxide (Azumax Co. Ltd. Ti-A KT881) (molecular weight: 476;vapor pressure: 1 Pa or below at 230° C.) (the mixed solution in whichthe ratio by weight of dibutyl carbonate to phenol was adjusted to65/35, and Ti as atoms was adjusted to about 10,000 ppm of the wholeliquid) from the middle stage of a continuous multi-stage distillationcolumn 3, which was composed of a condensation part, which was 2 inch inthe internal diameter, 0.5 m in the column length and filled with 10stages of sieve trays, and a recovery part which was 2 inch in theinternal diameter, 1 m in the column length and filled with Dixonpacking (6 mmφ) (at the time of supplying, the catalyst was dissolved inthe solution).

The condensation part was disposed in the lower part of the stage wherethe mixed solution was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. After the low boiling pointliquid mixture containing 1-butanol as a by-product was removed from thetop of the column through a line 4, and then it was liquefied by thecooler 5, and a part of it was removed continuously to a storage tank 8at 19 g/Hr and the rest was refluxed to the distillation column (refluxratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and the catalyst. The liquidremoved to the storage tank 8 was composed of 1-butanol: about 99% byweight, phenol: about 0.5% by weight, and dibutyl carbonate: about 0.2%by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bycontinuously supplying through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and the catalyst. The liquidremoved to the storage tank 20 was composed of 1-butanol: about 0.3% byweight, phenol: about 18% by weight, and dibutyl carbonate: about 81% byweight. No deposit or the like were found in the distillation column oninspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to a storage tank 48 at about8 g/Hr. After removing from the top of the column through a line 40, thedistillate was liquefied by a cooler 41 and was removed continuously tothe storage tank 44 at about 92 g/Hr. The liquid removed to a storagetank 44 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 94% by weight. White liquid that was solidifiedat ambient temperature was continuously removed to a storage tank 48 andcontained diphenyl carbonate: about 100% by weight, and butyl phenylcarbonate was below the detection limit. The analysis of the liquidindicated that Ti content was 0.8 ppm. No deposit or the like were foundin the distillation column on inspection.

Example 6

[Production of aromatic carbonate]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a transport line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, an organicpolytitanoxan composition (Nippon Soda Co. Ltd. B-4) containing butyltitanate tetramer (molecular weight: 970; vapor pressure: 1 Pa or belowat 230° C.), (the mixed solution in which the ratio by weight of dibutylcarbonate to phenol was adjusted to about 65/35, and Ti as atoms wasadjusted to about 10,000 ppm of the whole liquid, and this catalyst wasdissolved in this solution) from the middle stage of a continuousmulti-stage distillation column 3, which was composed of a condensationpart, which was 2 inch in the internal diameter, 0.5 m in the columnlength and filled with 10 stages of sieve trays, and a recovery partwhich was 2 inch in the internal diameter, 1 m in the column length andfilled with Dixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. The catalyst was dissolved inthe reaction liquid. After the low boiling point liquid mixturecontaining 1-butanol as a by-product was removed from the top of thecolumn through a line 4, and then it was liquefied by the cooler 5, anda part of it was removed continuously to a storage tank 8 at 19 g/Hr andthe rest was refluxed to the distillation column (reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and the catalyst. The liquidremoved to the storage tank 8 was composed of 1-butanol: about 99% byweight, phenol: about 0.5% by weight, and dibutyl carbonate: about 0.2%by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and the catalyst. The liquidremoved to the storage tank 20 was composed of 1-butanol: about 0.3% byweight, phenol: about 18% by weight, and dibutyl carbonate: about 81% byweight.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column is controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to a storage tank 48 at about8 g/Hr. After removing from the top of the column through the line 40,the distillate was liquefied by the cooler 41 and was removedcontinuously to the storage tank 44 at about 92 g/Hr. The liquid removedto the storage tank 44 is composed of dibutyl carbonate: about 6% byweight, butyl phenyl carbonate: about 94% by weight. White liquid thatwas solidified at ambient temperature was continuously removed to astorage tank 48 and contained diphenyl carbonate: about 100% by weight,and butyl phenyl carbonate was below the detection limit. The analysisof the liquid indicated that Ti content was below the detection limit.No deposit or the like were found in the distillation column oninspection.

Example 7

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through the preheater 2 and the transport line 1, a mixedsolution consisting of dibutyl carbonate, phenol and, as catalyst,monobutyltin butyloxide oxide (molecular weight: 660 or above; vaporpressure: 1 Pa or below at 230° C.) (the mixed solution in which theratio by weight of dibutyl carbonate to phenol was adjusted to about65/35, and Tin as atoms was adjusted to about 10,000 ppm of the wholeliquid, and this catalyst was dissolved in this solution) from themiddle stage of a continuous multi-stage distillation column 3, whichwas composed of a condensation part, which was 2 inch in the internaldiameter, 0.5 m in the column length and filled with 10 stages of sievetrays, and a recovery part which was 2 inch in the internal diameter, 1m in the column length and filled with Dixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. The catalyst was dissolved inthe reaction liquid. After the low boiling point liquid mixturecontaining 1-butanol as a by-product was removed from the top of thecolumn through a line 4, and then it was liquefied by the cooler 5, anda part of it was removed continuously to a storage tank 8 at 19 g/Hr andthe rest was refluxed to the distillation column (reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and the catalyst. The liquidremoved to the storage tank 8 was composed of 1-butanol: about 99% byweight, phenol: about 0.5% by weight, and dibutyl carbonate: about 0.2%by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight. The liquid removed to thestorage tank 20 was composed of 1-butanol: about 0.3% by weight, phenol:about 18% by weight, and dibutyl carbonate: about 81% by weight. Nodeposit or the like were found in the distillation column on inspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with the device shownin FIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to a storage tank 48 at about8 g/Hr. After removing from the top of the column through a line 40, thedistillate was liquefied by a cooler 41 and was removed continuously toa storage tank 44 at about 92 g/Hr. The liquid removed to the storagetank 44 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 94% by weight. White liquid that was solidifiedat ambient temperature was continuously removed to a storage tank 48 andcontained diphenyl carbonate: about 100% by weight, and butyl phenylcarbonate was below the detection limit. The analysis of the liquidindicated that Sn content was 0.9 ppm. No deposit or the like were foundin the distillation column on inspection.

Example 8

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, titanatecontaining butyl titanate hexamer [(BuO)₃—Ti—O—(Ti—(OBu)₂.O)₄—Ti—(OBu)₃](result of element analysis: C=48.3, H=9.1, O=21.9, Ti=20.7; sinceoxygen derived from BuO is 16.1, the number of bridging oxygen is 5,that is, there are 5 Ti—O—Ti bonds; molecular weight: 1390; vaporpressure: 1 Pa or below at 230° C.) (the mixed solution in which theratio by weight of dibutyl carbonate to phenol was adjusted to about65/35, and Ti as atoms was adjusted to about 10,000 ppm of the wholeliquid, and this catalyst was dissolved in this solution) from themiddle stage of the continuous multi-stage distillation column 3, whichwas composed of a condensation part, which was 2 inch in the internaldiameter, 0.5 m in the column length and filled with 10 stages of sievetrays, and a recovery part which was 2 inch in the internal diameter, 1m in the column length and filled with Dixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. The catalyst was dissolved inthe reaction liquid. After the low boiling point liquid mixturecontaining 1-butanol as a by-product was removed from the top of thecolumn through a line 4, and then it was liquefied by the cooler 5, anda part of it was removed continuously to a storage tank 8 at 19 g/Hr andthe rest was refluxed to the distillation column (reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and also the catalyst. Theliquid removed to the storage tank 8 was composed of 1-butanol: about99% by weight, phenol: about 0.5% by weight, and dibutyl carbonate:about 0.2% by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and the catalyst. The liquidremoved to the storage tank 20 was composed of 1-butanol: about 0.3% byweight, phenol: about 18% by weight, and dibutyl carbonate: about 81% byweight. No deposit or the like were found in the distillation column oninspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through the line 34 and reboiler 35, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column is controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to the storage tank 48 atabout 8 g/Hr. After removing from the top of the column through the line40, the distillate was liquefied by the cooler 41 and was removedcontinuously to the storage tank 44 at about 92 g/Hr. The liquid removedto a storage tank 44 is composed of dibutyl carbonate: about 6% byweight, butyl phenyl carbonate: about 94% by weight. White liquid thatwas solidified at ambient temperature was continuously removed to thestorage tank 48 and contained diphenyl carbonate: about 100% by weight,and butyl phenyl carbonate was below the detection limit. The analysisof the liquid indicated that Ti content was below the detection limit.No deposit or the like were found in the distillation column oninspection.

Example 9

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, an adductwith phenol of phenyl titanate tetramer[(PhO)₃—Ti—O—(Ti(OPh)₂—O)₂—Ti—(OPh)₃] (result of element analysis:C=65.2, H=4.8, O=17.6, Ti=12.4; According to ¹H-NMR analysis, PhOH andPhO groups exist at a ratio of 4:10. In one molecule, there are 4 Tiatoms and 3 oxygen atoms not derived from PhOH and PhO groups, that is,the number of bridging oxygen atoms is 3, and therefore 3 Ti—O—Ti bondsexist; molecular weight without the adduct phenol: 1170; vapor pressure:1 Pa or below at 230° C.) (the mixed solution in which the ratio byweight of dibutyl carbonate to phenol was adjusted to about 65/35, andTi as atoms was adjusted to about 10,000 ppm of the whole liquid)consisting of dibutyl carbonate, phenol and, as a catalyst, an adductwith phenol of phenyl titanate tetramer[(PhO)₃—Ti—O—(Ti(OPh)₂—O)₂—Ti—(OPh)₃] (result of element analysis:C=65.2, H=4.8, O=17.6, Ti=12.4; According to ¹H-NMR analysis, PhOH andPhO groups exist at a ratio of 4:10. In one molecule, there are 4 Tiatoms and 3 oxygen atoms not derived from PhOH and PhO groups, that is,the number of bridging oxygen atoms is 3, and therefore 3 Ti—O—Ti bondsexist; molecular weight without the adduct phenol: 1170; vapor pressure:1 Pa or below at 230° C.) from the middle stage of the continuousmulti-stage distillation column 3, which was composed of a condensationpart, which was 2 inch in the internal diameter, 0.5 m in the columnlength and filled with 10 stages of sieve trays, and a recovery partwhich was 2 inch in the internal diameter, 1 m in the column length andfilled with Dixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. After the low boiling pointliquid mixture containing 1-butanol as a by-product was removed from thetop of the column through a line 4, and then it was liquefied by thecooler 5, and a part of it was removed continuously to a storage tank 8at 19 g/Hr and the rest was refluxed to the distillation column (refluxratio=1.9). The catalyst was dissolved in the liquid phase.

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and the catalyst. The liquidremoved to the storage tank 8 was composed of 1-butanol: about 99% byweight, phenol: about 0.5% by weight, and dibutyl carbonate: about 0.2%by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and the catalyst. The liquidremoved to the storage tank 20 was composed of 1-butanol: about 0.3% byweight, phenol: about 18% by weight, and dibutyl carbonate: about 81% byweight. No deposit or the like were found in the distillation column oninspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to the storage tank 48 atabout 8 g/Hr. After removing from the top of the column through the line40, the distillate was liquefied by a cooler 41 and was removedcontinuously to a storage tank 44 at about 92 g/Hr. The liquid removedto a storage tank 44 is composed of dibutyl carbonate: about 6% byweight, butyl phenyl carbonate: about 94% by weight. White liquid thatwas solidified at ambient temperature was continuously removed to astorage tank 48 and contained diphenyl carbonate: about 100% by weight,and butyl phenyl carbonate was below the detection limit. The analysisof the liquid indicated that Ti content was below the detection limit.No deposit or the like were found in the distillation column oninspection.

Example 10

(Preparation of the catalyst)

To a reaction flask equipped with a stirrer, a thermometer, a heatingand cooling device and a reflux condenser, 3400 g (10 mol) oftetra-n-butoxytitanium and 1700 g of n-butanol were added and the liquidwas cooled to a temperature of 0° C. while being mixed well. Whilemaintaining the liquid temperature at 0° C., a mixture of 90 g (5 mol)of water and 2000 g of n-butanol was added slowly for 1 hour. After theaddition the temperature was raised to 80° C. and stirred for 5 hours.The flask was connected to a rotary evaporator equipped with a vacuumcontroller, vacuum pump and oil bath for heating after cooling down theliquid to room temperature (about 20° C.). The low boiling pointcomponents were distilled by reducing the pressure to about 25K Pa whilemaintaining the liquid temperature at 80° C. When almost all thedistillates came out, the temperature was raised slowly to 230° C. andfurther the pressure was reduced to 1 Pa, and after confirming thatthere were no distillate, nitrogen was added to return to normalpressure and the temperature was returned to room temperature (about 20°C.) to obtain about 2750 g of a pale yellow viscous liquid. This liquidis a catalyst A. The result of element analysis showed that thecomposition is C, 52.3%, H, 9.9%, Q: 20.4%, Ti: 17.4% and there is oneTi—O—Ti bond since the number of oxygen atoms except for the oxygenderived from BuO was 1 against Ti atom 2. Thus the catalyst A describedabove is presumed to be a mixture containing butyl titanate dimer[(BuO)₃—Ti—O—Ti (OBu)₃] as a main component.

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, the catalystA (the mixed solution in which the ratio by weight of dibutyl carbonateto phenol was adjusted to about 65/35, and Ti as atoms was adjusted toabout 10,000 ppm of the whole liquid, and this catalyst was dissolved inthis solution) from the middle stage of a continuous multi-stagedistillation column 3, which was composed of a condensation part, whichwas 2 inch in the internal diameter, 0.5 m in the column length andfilled with 10 stages of sieve trays, and a recovery part which was 2inch in the internal diameter, 1 m in the column length and filled withDixon packing (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. The catalyst was dissolved inthe reaction liquid. After the low boiling point liquid mixturecontaining 1-butanol as a by-product was removed from the top of thecolumn through a line 4, and then it was liquefied by the cooler 5, anda part of it was removed continuously to a storage tank 8 at 19 g/Hr andthe rest was refluxed to the distillation column (reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and also the catalyst. Theliquid removed to the storage tank 8 was composed of 1-butanol: about99% by weight, phenol: about 0.5% by weight, and dibutyl carbonate:about 0.2% by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, as in thecase of the continuous multi-stage distillation column 3, was composedof a condensation part, which is 2 inch in the internal diameter, 0.5 min the column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and the catalyst. The liquidremoved to the storage tank 20 was composed of 1-butanol: about 0.3% byweight, phenol: about 18% by weight, and dibutyl carbonate: about 81% byweight. No deposit or the like were found in the distillation column oninspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with a device shown inFIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by cooler 29 and was removed continuously to astorage tank 33 at about 80 g/Hr. The liquid removed to the storage tank33 is composed of dibutyl carbonate: about 6% by weight, butyl phenylcarbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to a storage tank 48 at about8 g/Hr. After removing from the top of the column through a line 40, thedistillate was liquefied by a cooler 41 and was removed continuously toa storage tank 44 at about 92 g/Hr. The liquid removed to the storagetank 44 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 94% by weight. White liquid that was solidifiedat ambient temperature was continuously removed to a storage tank 48 andcontained diphenyl carbonate: about 100% by weight, and butyl phenylcarbonate was below the detection limit. The analysis of the liquidindicated that Ti content was below the detection limit. No deposit orthe like were found in the distillation column on inspection.

Example 11

(Preparation of the catalyst)

To a reaction flask equipped with a stirrer, a thermometer, a heatingand cooling device and a reflux condenser, 3400 g (10 mol) oftetra-n-butoxytitanium and 1700 g of n-butanol were added and the liquidwas cooled to a temperature of 0° C. while being mixed well. Whilemaintaining the liquid temperature at 0° C., a mixture of 216 g (12 mol)of water and 2000 g of n-butanol was added slowly for 1 hour. After theaddition the temperature was raised to 80° C. and stirred for 5 hours.The flask was connected to a rotary evaporator equipped with a vacuumcontroller, vacuum pump and oil bath for heating after cooling down theliquid to room temperature (about 20° C.). The low boiling pointcomponents were distilled by reducing the pressure to about 25K Pa whilemaintaining the liquid temperature at 80° C. When almost all thedistillates came out, the temperature was raised slowly to 230° C. andfurther the pressure was reduced to 1 Pa, and after confirming thatthere were no distillate, nitrogen was added to return to normalpressure and the temperature was returned to room temperature (about 20°C.) to obtain about 2320 g of pale yellow viscous liquid. This liquid isa catalyst B. The result of element analysis showed that the compositionis C, 48.3%, H, 9.1%, O: 21.9%, Ti: 20.7%, and the number of bridgingoxygen atoms was 5 since the oxygen atom derived from BuO was 16.1, andthere were 5 Ti—O—Ti bonds. The molecular weight was 1390 and the vaporpressure was 1 Pa or less at 230° C. Thus the catalyst B described aboveis presumed to be a mixture containing butyl titanate hexamer[(BuO)₃—Ti—O—(Ti(OBu)₂—O)₄—Ti—(OBu)₃] as a main component.

[Production of aromatic carbonic acid ester]

Aromatic carbonate was produced using a device shown in FIG. 1. Thereaction was carried out by supplying continuously at a rate of about109 g/Hr, through a preheater 2 and a line 1, a mixed solutionconsisting of dibutyl carbonate, phenol and, as a catalyst, the catalystB (in which the ratio by weight of dibutyl carbonate to phenol wasadjusted to about 65/35, and Ti as atoms was adjusted to about 10,000ppm of the whole liquid, and this catalyst was dissolved in thissolution) from the middle stage of a continuous multi-stage distillationcolumn 3, which was composed of a condensation part, which was 2 inch inthe internal diameter, 0.5 m in the column length and filled with 10stages of sieve trays, and a recovery part which was 2 inch in theinternal diameter, 1 m in the column length and filled with Dixonpacking (6 mmφ).

The condensation part was disposed in the lower part of the stage wherethe mixture was supplied continuously, and the recovery part wasdisposed in the upper part. The heat required for the reaction anddistillation was supplied by circulating the liquid in the lower part ofthe column through a line 10 and a reboiler 11, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 230° C. The reaction liquid was continuously removed from thebottom of the continuous multi-stage distillation column 3 through theline 10 to a storage tank 12 at 90 g/Hr. The catalyst was dissolved inthe reaction liquid. After the low boiling point liquid mixturecontaining 1-butanol as a by-product was removed from the top of thecolumn through a line 4, and then it was liquefied by the cooler 5, anda part of it was removed continuously to a storage tank 8 at 19 g/Hr andthe rest was refluxed to the distillation column (reflux ratio=1.9).

The liquid removed to the storage tank 12 was composed of phenol: about23% by weight, dibutyl carbonate: about 56% by weight, butyl phenylcarbonate: about 12% by weight, diphenyl carbonate: about 0.2% byweight, 1-butanol: about 0.3% by weight and also the catalyst. Theliquid removed to the storage tank 8 was composed of 1-butanol: about99% by weight, phenol: about 0.5% by weight, and dibutyl carbonate:about 0.2% by weight.

After the reaction in the continuous multi-stage distillation column 3,the reaction was carried out using a continuous multi-stage distillationcolumn 15. The continuous multi-stage distillation column 15, like thecontinuous multi-stage distillation column 3, was composed of acondensation part, which is 2 inch in the internal diameter, 0.5 m inthe column length and filled with 10 stages of sieve trays, and arecovery part which is 2 inch in the internal diameter, 1 m in thecolumn length and filled with Dixon packing (6 mmφ), and thecondensation part was disposed in the lower part of the stage where thereaction liquid containing the catalyst was supplied continuously fromthe storage tank 12 to this distillation column 15, and the recoverypart was disposed in the upper part. The reaction was carried out bysupplying continuously through a line 13 the reaction liquid, which wasremoved from the bottom of the continuous multi-stage distillationcolumn 3 through the line 10 to the storage tank 12, to the continuousmulti-stage distillation column 15 at 100 g/Hr after preheating with apreheater 14.

The heat required for the reaction and distillation was supplied bycirculating the liquid in the lower part of the column through a line 22and a reboiler 24, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 220° C. The reactionliquid was continuously removed from the bottom of the continuousmulti-stage distillation column 15 through the line 22 to a storage tank24 at 17 g/Hr. After the low boiling point liquid mixture containingdibutylcarbonate as a by-product was removed from the top of the columnthrough a line 16, and then it was liquefied by a cooler 17, and a partof it was removed continuously to a storage tank 20 at 83 g/Hr and therest was refluxed to the distillation column (reflux ratio=4). Theliquid removed to the storage tank 24 was composed of dibutyl carbonate:about 5% by weight, butyl phenyl carbonate: about 74% by weight,diphenyl carbonate: about 10% by weight and the catalyst. The liquidremoved to the storage tank 20 was composed of 1-butanol: about 0.3% byweight, phenol: about 18% by weight, and dibutyl carbonate: about 81% byweight. No deposit or the like were found in the distillation column oninspection.

[Purification of diaryl carbonate]

Purification of diaryl carbonate was carried out with the device shownin FIG. 2. The distillation separation was carried out by continuouslyfeeding the liquid, which was removed to the storage tank 24, through aline 25 passing a preheater 26 at about 100 g/Hr to about 0.1 m abovethe middle stage of a continuous multi-stage distillation column 27,which was a column filled with Dixon packing (6 mmφ) with an internaldiameter of 2 inch and a length of 1 m. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column iscontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36 at about 20 g/Hr.

After removing from the top of the column through the line 28, thedistillate was liquefied by a cooler 29 and was removed continuously toa storage tank 33 at about 80 g/Hr. The liquid removed to the storagetank 33 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 86% by weight, diphenyl carbonate: about 7.5% byweight. The distillation separation was carried out by continuouslyfeeding the liquid, which was continuously removed to the storage tank33, through a line 37 passing a preheater 38 at about 100 g/Hr to themiddle stage of a continuous multi-stage distillation column 39, whichwas a column filled with Dixon packing (6 mmφ) with an internal diameterof 2 inch and a length of 2 m.

The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to a storage tank 48 at about8 g/Hr. After removing from the top of the column through a line 40, thedistillate was liquefied by a cooler 41 and was removed continuously tothe storage tank 44 at about 92 g/Hr. The liquid removed to the storagetank 44 is composed of dibutyl carbonate: about 6% by weight, butylphenyl carbonate: about 94% by weight. White liquid that was solidifiedat ambient temperature was continuously removed to a storage tank 48 andcontained diphenyl carbonate: about 100% by weight, and butyl phenylcarbonate was below the detection limit. The analysis of the liquidindicated that Ti content was below the detection limit. No deposit orthe like were found in the distillation column on inspection.

Example 12

(Preparation of the catalyst)

To a reaction flask equipped with a stirrer, a thermometer, a heatingand cooling device and a reflux condenser, 3400 g (10 mol) oftetra-n-butoxytitanium and 1700 g of n-butanol were added and the liquidwas cooled to a temperature of 0° C. while being mixed well. Whilemaintaining the liquid temperature at 0° C., a mixture of 90 g (5 mol)of water and 2000 g of n-butanol was added slowly for 1 hour. After theaddition the temperature was raised to 80° C. and stirred for 5 hours.The flask was connected to a rotary evaporator equipped with a vacuumcontroller, vacuum pump and oil bath for heating after cooling down theliquid to room temperature (about 20° C.). The low boiling pointcomponents were distilled by reducing the pressure to about 25K Pa whilemaintaining the liquid temperature at 80° C. When almost all thedistillates came out, the temperature was raised slowly to 230° C. andfurther the pressure was reduced to 1 Pa, and after confirming thatthere were no distillate, nitrogen was added to return to normalpressure and the temperature was returned to room temperature (about 20°C.) to obtain about 2750 g of pale yellow viscous liquid. This liquid isa catalyst A. The result of element analysis showed that the compositionis C, 52.3%, H, 9.9%, O: 20.4%, Ti: 17.4%, and there is one Ti—O—Ti bondsince the number of oxygen atoms except for the oxygen derived from BuOwas 1 against Ti atom 2. Thus the catalyst A described above is presumedto be a mixture containing butyl titanate dimer [(BuO)₃—Ti—O—Ti(OBu)₃]as a main component.

To this flask, the stirrer, thermometer, heating and cooling device andreflux condenser were reattached and the liquid was heated to 80° C.while stirring. While keeping the liquid temperature at 80° C., 4700 g(50 mol) of distilled and dehydrated phenol was added slowly. After theaddition, the liquid was heated to 180° C. and low boiling pointcomponents were evaporated. When there was almost no distillate, thetemperature of the liquid was slowly raised to 230° C. to removedistillates further. The flask was connected to the vacuum controllerand vacuum pump, the pressure was reduced slowly to 1 Pa and distillateswere removed. Then the flask was taken out of the oil bath, cooled toroom temperature (about 20° C.) and the inside pressure of the flask wasreturned to normal by nitrogen. Solid substance of about 4300 g with redorange coloring was obtained. This was the catalyst C. The result ofelement analysis showed that the composition is C, 64.5%, H, 4.5%, O:16.7%, Ti: 14.3%. The catalyst C described above is presumed to be amixture containing phenol adduct of phenyl titanate dimer[(PhO)₃—Ti—O—Ti(OPh)₃.2PhOH] as a main component.

[Production of aromatic carbonic acid ester]

A mixture consisting of dimethyl carbonate, phenol and, as a catalyst,the catalyst C was continuously supplied as a liquid from an inlet line50 through a preheater 51 to the location at 1 m from the top of amulti-stage distillation column 49 as shown in FIG. 3, which wascomposed of a packed column with 4 m tall and 3 inch internal diameterfilled with Dixon packing (6 mmφ) made of stainless steel. The heatrequired for the reaction and distillation was supplied by heating theliquid in the bottom of the column by the reboiler (the liquid supplyfrom the inlet line 50: 3.4 kg/Hr; composition of the liquid supply:DMC=about 68.3% by weight, PhOH=about 33.7% by weight, catalyst C=13.5mmol/Kg). The temperature at the bottom of the column was about 201° C.,the pressure at the top of the column was about 800 KPa, the refluxratio was about 1. As the result of the reaction, the liquid containingthe component of the catalyst, and methyl phenyl carbonate and diphenylcarbonate, which were the reaction products, was obtained from thebottom 53 of the column through lines 58 and 60. The gas distillate froma line 54 disposed on the top 52 of the column was condensed by acondenser 55. A part of the condensed liquid was refluxed to adistillation column 49 through an inlet line 56, and the rest wasremoved from a line 57. From this condensed liquid a low boiling pointproduct, methanol, was obtained. The amount of liquid removed from theline 60 (average liquid composition: methyl phenyl carbonate=50 g/Kg·Hr,diphenyl carbonate=0.4 g/Kg/Hr) was about 2.3 Kg/Hr. No deposit or thelike were found in the distillation column on inspection.

[Purification of aromatic carbonate]

Aromatic carbonate was purified using a device shown in FIG. 2. Thedevice was a continuous multi-stage distillation column which wascomposed of a column with 2 inch internal diameter and 1 m height,filled with Dixon packing (6 mmφ). Distillation separation was carriedout by feeding the liquid removed from the aforementioned line 60,continuously at a rate of about 100 g/Hr, through a line 25 and apreheater 26, to a continuous multi-stage distillation column 27 at thelocation about 0.1 m above the middle stage. The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 34 and a reboiler 35, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 210° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 27 through the line 34 to the storage tank 36. After removingfrom the top of the column through a line 28, the distillate wasliquefied by a cooler 29 and was removed continuously to a storage tank33. Distillation separation was carried out by feeding the liquid, whichwas removed continuously from the storage tank 33, continuously at arate of about 100 g/Hr, through a line 37 and the preheater 38, to themiddle stage of a continuous multi-stage distillation column 39, whichwas composed of a column with 2 inch internal diameter and 2 m height,filled with Dixon packing (6 mmφ). The heat required for thedistillation separation was supplied by circulating the liquid in thelower part of the column through a line 46 and a reboiler 47, and thetemperature at the bottom of the multi-stage distillation column wascontrolled to be about 230° C. The bottom liquid was continuouslyremoved from the bottom of the continuous multi-stage distillationcolumn 39 through a line 46 to a storage tank 48. After being removedfrom the top of the column through a line 40, the distillate wasliquefied by a cooler 41 and was removed continuously to a storage tank44. The liquid removed to the storage tank 44 contained methyl phenylcarbonate at about 94% by weight. The analysis of the liquid indicatedthat Ti content was below the detection limit. No deposit or the likewere found in the distillation column on inspection.

Comparative Example 2

Aromatic carbonate was purified as in Example 12 except that thecatalyst was changed from the catalyst C to phenoxy titanate [Ti(OPh)₄](molecular weight: 420, vapor pressure: about 15 Pa at 230° C.). Theamount of the liquid (average composition: methyl phenyl carbonate=50g/Kg·Hr, diphenyl carbonate=0.4 g/Kg/Hr) removed from the line 60 wasabout 2.3 Kg/Hr. The liquid removed to the storage tank 44 containedmethyl phenyl carbonate: about 94% by weight. The analysis of the liquidindicated that Ti was detected at 9 ppm. Inspection of the inside of thecolumn revealed white deposits on the wall of the distillation columnand the packing.

Example 13

(Preparation of the catalyst)

To a reaction flask equipped with a stirrer, a thermometer, a heatingand cooling device and a reflux condenser, 3400 g (10 mol) oftetra-n-butoxytitanium and 1700 g of n-butanol were added and the liquidwas cooled to a temperature of 0° C. while being mixed well. Whilemaintaining the liquid temperature at 0° C., a mixture of 90 g (5 mol)of water and 2000 g of n-butanol was added slowly for 1 hour. After theaddition, the temperature was raised to 80° C. and stirred for 5 hours.The flask was connected to a rotary evaporator equipped with a vacuumcontroller, vacuum pump and oil bath for heating after cooling down theliquid to room temperature (about 20° C.). The low boiling pointcomponents were distilled by reducing the pressure to about 25 KPa whilemaintaining the liquid temperature at 80° C. When almost all thedistillates came out, the temperature was raised slowly to 230° C. andthe pressure was reduced further to 1 Pa, and after confirming thatthere were no distillate, nitrogen was added to return to normalpressure and the temperature was returned to room temperature (about 20°C.) to obtain about 2750 g of pale yellow viscous liquid. This liquid isa catalyst A. The result of element analysis showed that the compositionis C, 52.3%, H, 9.9%, O: 20.4%, Ti: 17.4%, and there is one Ti—O—Ti bondsince the number of oxygen atoms except for the oxygen derived from BuOwas 1 against Ti atom 2. Thus the catalyst A described above is presumedto be a mixture containing butyl titanate dimer [(BuO)₃—Ti—O—Ti (OBu)₃]as a main component.

To this flask, the stirrer, thermometer, heating and cooling device andreflux condenser were reattached and the liquid was heated to 80° C.while being stirred. While keeping the liquid temperature at 80° C.,4700 g (50 mol) of distilled and dehydrated phenol was added slowly.After the addition, the liquid was heated to 180° C. and low boilingpoint components were evaporated. When there was almost no distillate,the temperature of the liquid was slowly raised to 230° C. to furtherremove distillates. The flask was connected to the vacuum controller andvacuum pump, the pressure was reduced slowly to 1 Pa and distillateswere removed. Then the flask was taken out of the oil bath, cooled toroom temperature (about 20° C.) and the inside pressure of the flask wasreturned to normal by nitrogen. Solid substance of about 4300 g with redorange coloring was obtained. This was the catalyst C. The result ofelement analysis showed that the composition is C, 64.5%, H, 4.5%, O:16.7%, Ti: 14.3%. The catalyst C described above is presumed to be amixture containing phenol adduct of phenyl titanate dimer[(PhO)₃—Ti—O—Ti(OPh)₃.2PhOH] as a main component.

[Production of aromatic carbonic acid ester]

A mixture consisting of methyl phenyl carbonate (MPC) and the catalystwas continuously supplied as a liquid from an inlet line 62 through apreheater 63 to the location at 1 m from the top of a multi-stagedistillation column 61 as shown in FIG. 4, which was composed of apressure control device 68 and a packed column with 4 m tall and 3 inchinternal diameter packed with Dixon packing (6 mmφ) made of stainlesssteel, and the reaction was carried out by heating with the reboiler(the liquid supply from the inlet line 62: 4.2 Kg/Hr; composition of theliquid supply: MPC=about 99% by weight, catalyst C=12.5 mmol/Kg). Thetemperature at the bottom of the column was about 195° C., the pressureat the top of the column was about 30 KPa, the reflux ratio was about2.1. As the result of the reaction, the liquid containing diphenylcarbonate, which was the reaction product, was obtained from the bottom65 of the continuous multi-stage distillation column through the outlet70 of the column bottom liquid. The gas distillate from a gas outlet 66disposed on the top 64 of the column was condensed by a condenser 67. Apart of the condensed liquid was refluxed, and the rest was removed froman outlet 69 of the condensed liquid. From this condensed liquid aby-product, dimethyl carbonate, was obtained. From the liquid removedfrom the line 70, diphenyl carbonate was obtained at a rate of 705g/Kg/Hr. No deposit or the like were found in the distillation column oninspection.

[Purification of aromatic carbonate]

Aromatic carbonate was purified using a device shown in FIG. 2. Thedevice was a continuous multi-stage distillation column which wascomposed of a column with 2 inch internal diameter and 1 m tall, filledwith Dixon packing (6 mmφ). Distillation separation was carried out byfeeding the liquid removed from the aforementioned line 60, continuouslyat a rate of about 100 g/Hr, through a line 25 and a preheater 26, to acontinuous multi-stage distillation column 27 at the location about 0.1m above the middle stage. The heat required for the distillationseparation was supplied by circulating the liquid in the lower part ofthe column through a line 34 and a reboiler 35, and the temperature atthe bottom of the multi-stage distillation column was controlled to beabout 210° C. The bottom liquid was continuously removed from the bottomof the continuous multi-stage distillation column 27 through the line 34to a storage tank 36. After removing from the top of the column throughthe line 28, the distillate was liquefied by a cooler 29 and was removedcontinuously to a storage tank 33. Distillation separation was carriedout by feeding the liquid, which was removed continuously from thestorage tank 33, continuously at a rate of about 100 g/Hr, through aline 37 and a preheater 38, to the middle stage of the continuousmulti-stage distillation column 39, which was composed of a column with2 inch internal diameter and 2 m height, filled with Dixon packing (6mmφ). The heat required for the distillation separation was supplied bycirculating the liquid in the lower part of the column through a line 46and a reboiler 47, and the temperature at the bottom of the multi-stagedistillation column was controlled to be about 230° C. The bottom liquidwas continuously removed from the bottom of the continuous multi-stagedistillation column 39 through the line 46 to a storage tank 48. Afterbeing removed from the top of the column through the line 40, thedistillate was liquefied by a cooler 41 and was removed continuously toa storage tank 44. To a storage tank 48, white liquid which wassolidified at ambient temperature was continuously removed and this wasdiphenyl carbonate, about 100% by weight. The analysis of the liquidindicated that Ti content was below the detection limit. No deposit orthe like were found in the distillation column on inspection.

Comparative Example 3

Aromatic carbonate was purified as in Example 13 except that thecatalyst was changed from the catalyst C to phenol adduct of phenoxytitanate [Ti(OPh)₄.2PhOH] (molecular weight without phenol adduct: 420,vapor pressure: about 15 Pa at 230° C.) (the liquid supplied from theinlet line 62: 4.2 Kg/Hr; composition of the liquid supplied: MPC=about99 wt. %, catalyst C=12.5 mmol/Kg). The temperature at the bottom of thecolumn was about 195° C., the pressure at the top of the column wasabout 30 KPa, and the reflux ratio was about 2.1. To the storage tank48, white liquid which was solidified at ambient temperature wascontinuously removed and this was diphenyl carbonate, about 100% byweight. The analysis of the liquid indicated that Ti was detected at 5ppm. Inspection of the inside of the column revealed white deposits onthe wall of the distillation column and the packing.

Example 14

(Polycarbonate was obtained from diphenyl carbonate produced by themethod for production in Example 1)

Diphenyl carbonate obtained in Example 1: 23.5 g and bisphenol A: 22.8 gwere put in a vacuum reactor equipped with a stirrer and polymerized at8000 Pa for 30 minutes and 4000 Pa for 90 minutes while being purgedwith nitrogen gas. After this, temperature was raised to 270° C. andpolymerization was continued at 70 Pa for 1 hour. Aromatic polycarbonateobtained in such a way was transparent without coloring and goodquality. The number average molecular weight was 10,500.

Comparative Example 4

(Polycarbonate was obtained from diphenyl carbonate produced by themethod for production in comparative Example 1)

Diphenyl carbonate obtained in Example 3: 23.5 g and bisphenol A: 22.8 gwere put in a vacuum reactor equipped with a stirrer and polymerized at8000 Pa for 30 minutes and 4000 Pa for 90 minutes while being purgedwith nitrogen gas. After this, temperature was raised to 270° C. andpolymerization was continued at 70 Pa for 1 hour. Aromatic polycarbonateobtained in such a way had red coloring and the number average molecularweight was 9,800.

INDUSTRIAL APPLICABILITY

According to the present invention, high purity diaryl carbonate can beproduced with a catalyst easily removed when producing aromaticcarbonate by an transesterification of a starting material and areactant in the presence of a metal-containing catalyst while distillingoff by-product alcohol and/or by-product dialkyl carbonate to theoutside of the reaction system. An aromatic polycarbonate produced bytransesterification comprising diaryl carbonate produced by the methodof the present invention is free from coloring and has high quality.

1. A method for producing an aromatic carbonate, which comprisesallowing to react a starting material selected from the group consistingof a dialkyl carbonate represented by the following formula (1), analkylaryl carbonate represented by the following formula (2) and amixture thereof with a reactant selected from the group consisting of anaromatic monohydroxy compound represented by the following formula (3),an alkylaryl carbonate represented by the following formula (4) and amixture thereof in the presence of a metal-containing catalyst, whiledistilling off by-product alcohols and/or by-product dialkyl carbonatesto the outside of the reaction system, thereby producing an aromaticcarbonate represented by the following formula (5) and/or the followingformula (6) corresponding to the starting material and the reactant,wherein the metal-containing catalyst is an organic polytitanoxanecompound of a molecular weight of 480 or more which comprises at leasttwo titanium atoms and is dissolved in a liquid phase in the reactionsystem or present in the form of liquid during the reaction,

wherein R¹, R² and R³ in the formulas (1) to (4) independently representan alkyl group having 1 to 10 carbon atoms, an alicyclic group having 3to 10 carbon atoms or an aralkyl group having 6 to 10 carbon atoms, andAr¹, Ar² and Ar³ independently represent an aromatic group having 5 to30 carbon atoms, and

wherein R in the formula (5) is selected from R¹, R², R³ of thecorresponding starting material and reactant, and Ar in the formulas (5)and (6) is selected from Ar¹, Ar² and Ar³ of the corresponding startingmaterial and reactant, respectively.
 2. The method according to claim 1,wherein said organic polytitanoxane compound contains at least onealkoxy group and/or aryloxy group as an organic group.
 3. The methodaccording to claim 1, wherein said organic polytitanoxane compound isobtained by a polycondensation reaction of at least one raw materialselected from the group consisting of tetraalkoxytitanium,tetrahalotitanium (TiX_(4:) X being selected from Cl and Br) andtitanium hydroxide.
 4. The method according to claim 3, wherein saidorganic polytitanoxane compound is obtained by sequentially orsimultaneously performing two steps of: 1) preparing a partiallyhydrolyzed product by partially hydrolyzing tetraalkoxytitanium and 2)distilling off a generated low boiling point component including alcoholfrom the partially hydrolyzed product and subjecting the product topolycondensation.
 5. The method according to claim 3, wherein saidorganic polytitanoxane compound is obtained by subjectingtetraalkoxytitanium to heating, deetherification and polycondensation.6. The method according to claim 3, wherein said organic polytitanoxanecompound is obtained by sequentially or simultaneously performing threesteps of: 1) preparing a partially hydrolyzed product by partiallyhydrolyzing tetrahalotitanium, 2) distilling off a low boiling pointcomponent from the partially hydrolyzed product and subjecting theproduct to polycondensation and 3) reacting the resultant with alcohol,removing HX therefrom and alkoxylating the same.
 7. The method accordingto claim 1, wherein said organic polytitanoxane compound is used as isor after alkoxy group exchange by reacting the composition with acomposition containing at least one member selected from alcohol, anaromatic hydroxy compound and carbonic acid ester.
 8. The methodaccording to claim 1, wherein said organic polytitanoxane compoundcontains at least two Ti atoms in one molecule.
 9. The method accordingto claim 8, wherein said organic polvtitanoxane compound contains 2 to 6Ti atoms in one molecule.
 10. The method according to claim 8, whereinsaid organic polytitanoxane compound contains at least one Ti—O—Ti bondin one molecule.
 11. The method according to claim 1, wherein saidorganic polytitanoxane compound has a vapor pressure at 230° C. of 10 Paor lower.
 12. The method according to claim 1, wherein said organicpolytitanoxane compound is used in a proportion of 0.0001 to 30% byweight based on the total weight of said starting material and saidreactant.
 13. The method according to claim 1, wherein said aromaticmonohydroxy compound is phenol.
 14. The method according to claim 6,wherein said organic polytitanoxane compound is used as is or afteralkoxy group exchange by reacting the composition with a compositioncontaining at least one member selected from alcohol, an aromatichydroxy compound and carbonic acid ester.
 15. The method according toclaim 14, wherein said organic polytitanoxane compound contains at leasttwo Ti atoms in one molecule.
 16. The method according to claim 15,wherein said organic polytitanoxane compound contains 2 to 6 Ti atoms inone molecule.
 17. The method according to claim 15, wherein said organicpolytitanoxane compound contains at least one Ti—O—Ti bond in onemolecule.
 18. The method according to claim 11, wherein said organicpolytitanoxane compound is used in a proportion of 0.0001 to 30% byweight based on the total weight of said starting material and saidreactant.
 19. The method according to claim 18, wherein said aromaticmonohydroxy compound is phenol.